From realme Community App:
Steps:
1. Turn on realme Community App, log in and click the avatar(me).
2. Click the edit icon on the top right. Then you can see your User ID.
From realme Community website:
Steps:
1. Go to realme Community website https://c.realme.com/in/.
2. Log in to your realme account and click the "Message".
3. Click the Edit icon