Operating system: iOS 14.4. 1.

1. Take Apple 7 as an example, and click Settings on the phone screen, as shown below.

2. Drop down and click GM on the page, as shown in the figure below.

3. Click Access Restrictions, as shown in the figure below.

4. Click Enable Access Restrictions, as shown below

5. Then enter the password for access restriction, as shown below.

6. After entering the access restriction page, just turn the allow switch on the right side of the application you want to encrypt, as shown below.