Here's how:

Begin with creating a PayPal app to obtain the required access token.

1. Log in to PayPal Developer.
2. Go to the My Apps & Credentials page and toggle to Sandbox or Live, depending on which environment you want to work in.
3. In the REST API apps section, click Create App.
4. Enter an App Name and click Create App.
5. Review and edit the app details.
6. Click Save.

Here is how to get the access token:

1. Make a /token call with your app’s OAuth client_id and secret keys for the basic authentication values. In the request body, set grant_type to client_credentials.
2. Run the command. PayPal generates and returns an access token.

Sample access token request:
 

curl -v​ https://api.sandbox.paypal.com/v1/oauth2/token \
   -H "Accept: application/json" \
   -H "Accept-Language: en_US" \
   -u "EOJ2S-Z60oN_le_KS1d75wsZ6y0SFdVsY9183IvxFyZp:EC1usMEUk8e9ihI7ZdXLF5cz6y0SFdVsY9183IvxFyZp"
   -d "grant_type=client_credentials"