Generate Access And Refresh Tokens for Integration

Make sure you have already created a project to enable APIs. To create, refer Create a Project in Google Developer Console.
Make sure you have already enabled the Google Drive API to create application. To enable, refer Enable Google Drive API.
Make sure you have already created an application to generate OAuth client credentials. To create, refer Create Application in Google Developer Console.
Make sure you have already generated OAuth credentials to generate access and refresh tokens. To generate OAuth credentials, refer Generate OAuth Client Credentials.

Navigate to the below url.
https://developers.google.com/oauthplayground/
Click the gear icon located on the top right corner for OAuth configuration.
Enable Use your own OAuth credentials checkbox and enter Client ID and Client secret details in the text boxes provided.
In the left side section, click Drive API v3 and select the first one as shown below.
Click Authorize APIs button.
Select your google account and click Allow to give access.
Click Exchange authorization code for tokens button.
Copy the Refresh and Access tokens.