Open Facebook and go to Settings & privacy
Tap Settings
Go to Privacy Checkup
Set Who can see your future posts? to Friends
Change Limit past posts to Friends
Set Who can see your friends list? to Only me
Set Who can see your email address? to Only me
Set Who can see your phone number? to Only me
Set Who can look you up using the email address you provided? to Friends or Only me
Set Who can look you up using the phone number you provided? to Friends or Only me
Turn off search engine linking to your profile
Set Who can send you friend requests? to Friends of friends
Set Who can see your profile picture? to Friends
Set Who can see your cover photo? to Friends
Set Who can see your stories? to Friends
Set Who can see your posts and stories on your profile? to Friends
Set Who can see posts you’re tagged in on your profile? to Friends
Review and remove public posts, photos, and videos
Review and delete or hide old posts from Public
Set timeline and tagging review to On
Set tag review to On
Set profile review for tags to On
Remove public info from About section
Set birthday visibility to Only me
Set relationship status visibility to Only me
Set hometown, workplace, education, and other profile details to Only me
Set past and future audience for each post to Friends or Only me
Check app and website permissions and remove unnecessary access
Turn off Active Status if you want to appear offline
Use the profile viewer or view-as option to check what non-friends can see