update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/application-dev/napi/napi-guidelines.md

 # Using Native APIs in Application Projects
 
-OpenHarmony applications use JavaScript (JS) when calling native APIs. The native APIs (NAPIs) provided by the [ace_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository are used to implement interaction with JS. Currently, the **ace_napi** repository supports some third-party **Node.js** interfaces. The names of the NAPIs are the same as those in the third-party **Node.js**. For details about the interfaces supported, see `libnapi.ndk.json` in this repository.
+OpenHarmony applications use JavaScript (JS) when calling native APIs. The native APIs (NAPIs) provided by the [ace_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository are used to implement interaction with JS. The names of the NAPIs are the same as those in the third-party **Node.js**. For details about the interfaces supported, see **libnapi.ndk.json** in the ace_napi repository.
 
 ## How to Develop
 
-The IDE has a default project that uses NAPIs. You can choose `File` > `New` > `Create Project` to create a `Native C++` project. The **cpp** directory is generated in the **main** directory. You can use the NAPIs provided by the **ace_napi** repository for development.
+The DevEco Studio has a default project that uses NAPIs. 
 
-You can `import` the native .so that contains the JS processing logic. For example, `import hello from 'libhello.so'` to use the **libhello.so** capability. Then, the JS object created using the NAPI can be passed to the `hello` object of the application to call the native capability.
+You can choose **File** > **New** > **Create Project** to create a **Native C++** project. The **cpp** directory is generated in the **main** directory. You can use the NAPIs provided by the **ace_napi** repository for development.
+
+You can import the native .so that contains the JS processing logic. For example, **import hello from 'libhello.so'** to use the **libhello.so** capability. Then, the JS object created using the NAPI can be passed to the **hello** object of the application to call the native capability.
 
 ## Development Guidelines
 
@@ -17,7 +19,7 @@ You can `import` the native .so that contains the JS processing logic. For examp
 
 ### .so Naming Rules
 
-Each module has a .so file. For example, if the module name is `hello`, name the .so file `libhello.so`. The `nm_modname` field in `napi_module` must be `hello`, which is the same as the module name. The sample code for importing the .so file is `import hello from 'libhello.so'`.
+Each module has a .so file. For example, if the module name is **hello**, name the .so file **libhello.so**. The **nm_modname** field in **napi_module** must be **hello**, which is the same as the module name. The sample code for importing the .so file is **import hello from 'libhello.so'**.
 
 ### JS Objects and Threads
 
@@ -28,7 +30,7 @@ The Ark engine prevents NAPIs from being called to operate JS objects in non-JS
 
 ### Importing Header Files
 
-Before using NAPI objects and methods, include **napi/native_api.h**. Otherwise, when only the third-party library header file is included, an error will be reporting, indicating that the interface cannot be found.
+Before using NAPI objects and methods, include **napi/native_api.h**. Otherwise, if only the third-party library header file is included, an error will be reporting, indicating that the interface cannot be found.
 
 ### napi_create_async_work
 
@@ -50,11 +52,11 @@ napi_status napi_create_async_work(napi_env env,
 
 
 
-## Example 1: Encapsulating Synchronous and Asynchronous APIs for the Storage Module
+## Encapsulating Synchronous and Asynchronous APIs for the Storage Module
 
 ### Overview
 
-This example shows how to encapsulate the synchronous and asynchronous APIs of the storage module. The storage module implements the functions of storing, obtaining, deleting, and clearing data.
+This example shows how to encapsulate the synchronous and asynchronous APIs of the **Storage** module. The **Storage** module implements the functions of storing, obtaining, deleting, and clearing data.
 
 ### API Declaration
 
@@ -79,11 +81,11 @@ export default storage;
 
 ### Implementation
 
-You can obtain the complete code from `sample/native_module_storage/` in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
+You can obtain the complete code from sample/native_module_storage/ in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
 
-#### Registering the Module
+**1. Register the module.**
 
-Register four synchronous APIs (`getSync`, `setSync`, `removeSync`, and`clearSync`) and four asynchronous APIs (`get`, `set`, `remove`, and `clear`).
+Register four synchronous APIs (**getSync**, **setSync**, **removeSync**, and **clearSync**) and four asynchronous APIs (**get**, **set**, **remove**, and **clear**).
 
 ```c++
 /***********************************************
@@ -122,9 +124,9 @@ extern "C" __attribute__((constructor)) void StorageRegister()
 }
 ```
 
-#### Implementing getSync
+**2. Implement getSync.**
 
-The **getSync** function registered for the storage module is **JSStorageGetSync**. Obtain data from `gKeyValueStorage`, create a string object, and return it.
+The **getSync** function registered for the **Storage** module is **JSStorageGetSync**. Obtain data from **gKeyValueStorage**, create a string object, and return the object created.
 
 ```c
 static napi_value JSStorageGetSync(napi_env env, napi_callback_info info)
@@ -168,9 +170,9 @@ static napi_value JSStorageGetSync(napi_env env, napi_callback_info info)
 }
 ```
 
-#### Implementing get
+**3. Implement get().**
 
-The `get` function registered for the storage module is `JSStorageGet`.
+The **get** function registered for the **Storage** module is **JSStorageGet**.
 
 ```c
 static napi_value JSStorageGet(napi_env env, napi_callback_info info)
@@ -268,7 +270,7 @@ static napi_value JSStorageGet(napi_env env, napi_callback_info info)
 }
 ```
 
-### JS Sample Code
+**JS Sample Code**
 
 ```js
 import storage from 'libstorage.so';
@@ -292,11 +294,11 @@ export default {
 
 
 
-## Example 2: Binding Native and JS Objects for the NetServer Module
+## Binding Native and JS Objects for the NetServer Module
 
 ### Overview
 
-This example shows how to implement the `on/off/once` method and bind C++ and JS objects using the **wrap** API. The NetServer module implements the network service.
+This example shows how to implement the **on**, **off**, and **once** methods and bind C++ and JS objects using **wrap()**. The **NetServer** module implements the network service.
 
 ### API Declaration
 
@@ -312,9 +314,9 @@ export class NetServer {
 
 ### Implementation
 
-You can obtain the complete code from `sample/native_module_netserver/` in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
+You can obtain the complete code from **sample/native_module_netserver/** in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
 
-#### Registering the Module
+**1. Register the module.**
 
 ```c
 static napi_value NetServer::Export(napi_env env, napi_value exports)
@@ -338,7 +340,7 @@ static napi_value NetServer::Export(napi_env env, napi_value exports)
 }
 ```
 
-#### Binding C++ and JS Objects in a Constructor
+**2. Bind C++ and JS objects in a constructor.**
 
 ```c
 napi_value NetServer::JS_Constructor(napi_env env, napi_callback_info cbinfo)
@@ -365,7 +367,7 @@ napi_value NetServer::JS_Constructor(napi_env env, napi_callback_info cbinfo)
 }
 ```
 
-#### Obtaining the C++ Object from the JS Object
+**3. Obtain a C++ object from a JS object.**
 
 ```c
 napi_value NetServer::JS_Start(napi_env env, napi_callback_info cbinfo)
@@ -398,7 +400,7 @@ napi_value NetServer::JS_Start(napi_env env, napi_callback_info cbinfo)
 }
 ```
 
-After `netServer->Start` is executed, call back the `start` event registered by `on`.
+After **netServer->Start** is executed, call back the **start** event registered by **on()**.
 
 ```c
 int NetServer::Start(int port)
@@ -435,7 +437,7 @@ int NetServer::Start(int port)
 }
 ```
 
-#### Registering Events (on)
+**4. Call on() to register an event observer.**
 
 ```c
 napi_value NetServer::JS_On(napi_env env, napi_callback_info cbinfo)
@@ -475,7 +477,7 @@ napi_value NetServer::JS_On(napi_env env, napi_callback_info cbinfo)
 }
 ```
 
-### JS Sample Code
+**JS Sample Code**
 
 ```javascript
 import { NetServer } from 'libnetserver.so';
@@ -491,7 +493,7 @@ export default {
 
 
 
-## Example 3: Calling Back a JS API in a Non-JS Thread
+## Calling Back a JS API in a Non-JS Thread
 
 ### Overview
 
@@ -499,11 +501,11 @@ This example describes how to invoke a JS callback in a non-JS thread. For examp
 
 ### Implementation
 
-You can obtain the complete code from `sample/native_module_callback/` in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
+You can obtain the complete code from **sample/native_module_callback/** in the [OpenHarmony/arkui_napi](https://gitee.com/openharmony/arkui_napi/tree/master) repository.
 
-#### Registering the Module
+**1. Register the module.**
 
-Register the `test` API to pass in a parameter.
+Register the **test** API to pass in a parameter.
 
 ```c++
 /***********************************************
@@ -536,7 +538,7 @@ extern "C" __attribute__((constructor)) void CallbackTestRegister()
 }
 ```
 
-#### Obtaining the Loop in env and Throwing the Task to the JS Thread
+**2. Obtain the loop in env and throw the task to a JS thread.**
 
 ```c++
 #include <thread>
@@ -627,7 +629,7 @@ static napi_value JSTest(napi_env env, napi_callback_info info)
 }
 ```
 
-### JS Sample Code
+**JS Sample Code**
 
 ```js
 import callback from 'libcallback.so';