app signatures status from google billing (access to Google Play Android Developer API)

[daniel-aquere]

Hi everyone,
I have finished developing my app, and I will be selling signatures.
When a user purchases a signature, I save the following information: orderId, packageName, productId, purchaseTime, purchaseState, purchaseToken, quantity, autoRenewing, and acknowledged.
When the user logs in to my app, I need to inquire about the signature status from the Play Store (to enable access to app content), but I don't know how to do this.
I came across something related to generating a token using OAuth 2.0 authentication on Google Cloud, but it is unclear.
Exists another way to verify the signature status?
Could the community help me with this issue, please?
Many thanks for considering my request.
Daniel