You must have an online store (Woocommerce), if not do it first then get back and continue
Step 1: WordPress config
If you’re using non-pretty permalinks WooCommerce REST API will not work. Config pretty permalinks in Settings > Permalinks so that the custom endpoints are supported.
Step 2: Woocommerce config
Pre-generated keys can be used to authenticate use of the REST API endpoints. New keys can be generated either through the WordPress admin interface or they can be auto-generated through an endpoint.
Generating API keys in the WordPress admin interface
To create or manage keys for a specific WordPress user, go to WooCommerce > Settings > Advanced => REST API
Choose the level of access for this REST API key, which can be Read access, Write access or Read/Write access. Then click the “Generate API Key” button and WooCommerce will generate REST API keys for the selected user.
Click the “Add Key” button. In the next screen, add a description and select the WordPress user you would like to generate the key for. Use of the REST API with the generated keys will conform to that user’s WordPress roles and capabilities.
Now that keys have been generated, you should see consumerKey and consumerSecret.
Note: API keys are not transferred to other users.
Turn on payment gateway for WooCommerce
To turn on stripe and paypal gateway for WooCommerce, go to WooCommerce > Settings > Payments
Click Manage button to advance configuration for each payment gateway
Step 3: Install ZiniStoreAPI plugin
Install this plugin to your web store.
Then open App control
Click to settings under plugin name
Open file wp-config.php and add this config, don’t forget change xxxxxxxxxxx with your content. This file is located in the root of your WordPress file directory and contains your website’s base configuration details, such as database connection information.
Step 4: Enable user register