About adding contact

You can quickly identify which of your contacts are using Mixin Messenger by accessing your phone's address book.

1. Open Mixin Messenger and tap the avatar at the top right corner
2. Tap Add Contact > Add by Phone Contact

If you can't see your contacts, please check the following:

1. Ensure your contacts are using Mixin Messenger
2. Your contacts may change the Mixin settings that don't allow people to search his/her phone number;
3. You have allowed Mixin Messenger to access your phone's contact.

Note: 

You could disable Mixin Messenger to access the phone's contact at any time in your Phone's Settings. 

Resources:

How to find contacts?

How to add contacts and how to get friends?

How to hide my phone number?