PHP Oauth2 Grant_type cases based on custom data

I have a requirement which needs to generate a token code, and using this token, access to any kind of resources, however, I cannot find a oauth2 workflow to this specific case.

Let's some third party app will send me a request like

 grant_type="I DONT KNOW"&client_id=myapp&client_secret=mypass&phone=1234567

Based on this, I need to return some information regarding to the phone number, given the fact I've never used oauth, I was thinking about using User Credentials, but checking the sources, it only allows user and password.

Can anyone pls point me in the right direction?

Best Regards.