https://contactforhelp.com/blog/how-to-lock-facebook-profile-in-android/

Facebook is the most commonly used social media platform. And with so many users signed up on the same platform, privacy does become an issue. But Facebook does give you the option of locking your profile. Here’s #howtolockFacebookprofile. Open your profile and click on the lock profile option beside story feature. Go through the on-screen instructions and click on lock your profile under the drop down menu. #howtolockyourFacebookprofile.