Sometimes, Unity CS may ask you for your Gamer ID / Player ID / Account ID  to help confirm your eligibility for an offer or to verify that you completed an offer. While we refer to it as your Gamer/Player ID, it’s also common for app publishers to call it your User Account, Account ID, or something similar. The Player ID (or Account ID) is the unique identifier that allows an advertiser or publisher to locate your game profile; for most publishers, it will be a series of letters and/or numbers. Alternatively, some publishers might use the email address associated with your Google Play or Apple Game Center account.

To locate your ID in most apps, start by looking in the app's settings menu > account or within your character profile.

Here is an example of how to locate your ID:

Mech Arena

To find your Player ID - go to Settings > Profile