Open the System > Extensions > Integrations

Add New Integration

Set the integration Name and other settings, then specify your
Magento 2 back-end password in the Your Password field

Switch to the API sidebar tab and select the resources which will
be available to OAuth clients:

Press the Save button. The integration will be saved and the
Integrations list will be shown again. Press the Activate link in the integration row:

A confirmation screen will be shown. Press the Allow button

The credentials screen will be shown.
Use them in your third-party software to access your Magento 2 as OAuth server.
You will see:
- Consumer Key
- Consumer Secret
- Access Token
- Access Token Secret
Copy it to somewhere, then press the Done button.

The integration will be saved and the Integrations list will be
shown again. You will see your integration in the Active state:
