Privacy has always been a contentious issue on Facebook, but there are things users can do to protect their personal information on the platform. Of course, people can hide their Facebook profiles from strangers to prevent unsolicited interaction, but one of the best ways to keep a Facebook account private and keep stalkers at bay is to simply lock it up. The feature is designed to shield users' personal information from people who are not their friends and can be done on Android, iOS, and the web.
When a user locks their Facebook profile, it prevents strangers from seeing most of their personal information, including friends list, stories, posts, and most other details. Locking a profile also means that only friends can see their full-size profile photo and cover photo for enhanced privacy. What's more, all their 'Public' posts will also be visible only to friends rather than everybody on Facebook. Users can easily lock their profiles across all available platforms.
To lock a Facebook profile using the mobile app, first tap on the profile avatar on the top-left. Then hit the three-dot menu button on the right, next to the 'Edit Profile' button. On the next screen, simply select 'Lock Profile' and then confirm the decision on the next page by tapping on the blue 'Lock your profile' button at the bottom. This should lock that Facebook profile and prevent that user's personal information from being shown to people who are not their friends on Facebook. The process is identical on Android and iOS.
The 'Lock Profile' Option Is Available Only On Facebook's Mobile Site
Users can also lock their profile using the Facebook website, but it's not as straightforward as one would have liked. Facebook's desktop site does not offer the 'Lock Profile' option, which means users have to navigate to the mobile site, which does. While the workaround is easy enough, it is still a bit of an annoyance, something that Facebook should look into. That said, it is the only available method at this point for people wanting to lock their profile via the website.
For people who'd rather use the website to lock their profile, log into the Facebook mobile site (m.facebook.com) and click on the profile avatar at the top-left. Next, hit the three-dot menu button next to the blue 'Edit Profile' button, and on the pop-up menu, select 'Lock Profile.' Finally, confirm the decision by clicking on the 'Lock your profile' button on the next page.
Source: Facebook