You need both numbers to receive diamonds. Here is where to find them.
To top up Mobile Legends: Bang Bang, you need two numbers: your User ID and your Zone ID. If one of them is wrong, the diamonds go to the wrong account or the top-up fails.
Go to the official Mobile Legends redemption page, enter the User ID, the Zone ID and the code, then confirm. The diamonds usually appear within a few minutes.
Sending diamonds to a friend? Ask for their User ID and Zone ID. You never need their password.