The following is a screenshot of the steps:
1. Log in to the homepage of official WeChat account and drop it down. Find Settings-Security Center.
2. Click to enter the security center, and you will see an administrator micro-signal option. Click on the details on the right.
3. After entering, you can add the operator's micro signal. Operators can log in to their accounts and send messages in groups. As shown below.
Note: Administrator WeChat can't be changed casually unless the other person is someone you trust very much.