How to lock Facebook profile

To lock your Facebook profile, you can follow these steps:

1. Log in to your Facebook account.
2. Click on the down arrow in the top-right corner of the page, and then select "Settings & Privacy."
3. Click on "Privacy" from the left-side menu.
4. Scroll down to the "Who can see my stuff?" section, and then click on "Edit" next to "Who can see your future posts."
5. Choose "Friends" from the drop-down menu, or you can choose a custom setting if you prefer.
6. Scroll down to the "Limit the audience for posts you've shared with friends of friends or public?" section, and then click on "Limit Past Posts."
7. Click on "Confirm" to lock your past posts with your friends.

Note: Locking your profile means that only your friends will be able to see your future posts and any posts you have made public in the past. Keep in mind that your profile picture and cover photo will still be visible to the public.