The Privacy tab controls who can see what you post and who can contact and find you. If you only change the settings in one place, this should be it (but you really should change all the settings we're mentioning here).
In the "Who can see my stuff?" menu, set "Who can see your future posts?" to Friends. Then click the "Limit Past Posts" link and then the "Limit Old Posts" button. This changes any old posts marked as "Public" to "Friends."
From here you can also access the Activity Log. This lets you review old posts, photos and more in your timeline to get rid of things you don't want people to see anymore. Learn more about using the Activity Log to protect your privacy.
In the "Who can contact me?" section, change "Who can send you friend requests?" to "Friends of Friends." This keeps strangers from sending you friend invites you don't want. The exception is if you want old friends from school to be able to send you friend requests.
Under "Who can look me up?" you want to change the settings to "Friends," "Friends" and "No." This makes it much harder for strangers or stalkers to find you if they just have a phone number, email address or know your name. Keep in mind, this will also stop old friends from easily finding you.
Timeline and Tagging
We've already limited who can see your posts, but the Timeline and Tagging tab has a few privacy loopholes you need to close.
In "Who can add things to my timeline?" you definitely want to limit who can post on your timeline to just "Friends." If you really want to make sure you control everything people see on your timeline, you can change that to "Only Me."
Also, be sure to set "Review posts..." to "On." That way if a friend mentions you in a post you don't necessarily agree with or would make you look bad to your friends, you can stop it before it appears.
In "Who can see things on my timeline?" you can leave "Who can see posts you've been tagged in..." to "Friends of Friends," since they'll be able to see the post on your friend's timeline anyway. If you want to be extra cautious, though, set it to "Friends." You do, however, want "Who can see what others post on your timeline?" set to "Friends."
Bonus Tip: In the "Who can see things on my timeline?" section, click the "View As..." link to see what your timeline looks like to strangers. This will quickly reveal if there's something showing that shouldn't be.
In "How can I manage tags people add and tagging suggestions?" you can set the settings to "On," "Only Me" and "No One." This keeps things you're tagged in, like photos, from automatically being visible to all your friends. It also keeps you from being tagged in photos you don't control, which can give away your face and name to people you don't know.
Facebook is great for staying in touch with people, but some people you don't want in your life. That's where Facebook's Blocking feature comes in handy.
You can block individual users on Facebook and in Facebook Messenger; stop seeing app invitations and events from certain people; and block apps themselves or even block Facebook Pages.
If you want to see who you're already blocking, their names will show up under the Block users search box. From there you can unblock people you might have blocked in the past.
We're going to jump over "Language," which lets you set the language Facebook appears in; "Notifications," which lets you control how often Facebook bugs you in your email, text messages and elsewhere; and "Mobile," which gives you control over which cellphones are linked with Facebook and how often it can bug you. These aren't really areas of security or privacy concern, but we do encourage you to check those out on your own because they can make Facebook less annoying.
The Apps settings involve more than just controlling what Facebook apps you have linked to your account. It has a few settings that are serious privacy problems if they aren't changed.
Over the years, the "Apps" section has evolved quite a bit, and tweaking the settings for maximum safety could be an article on its own. In fact, we went ahead and wrote one, so be sure to check it out so you stay as safe as possible.
If you're short on time, however, under "Apps, Websites and Plugins" click the "Edit" button. Then choose the "Disable Platform" link in the bottom right corner. This will completely turn off apps, and stop app developers from collecting information about you.
Warning! If you select Disable Platform you will not be able to log into websites or applications using Facebook. You won't be able to log into mobile games or applications using Facebook. There are other things that you will no longer be able to do as well. Make sure to read this list of what is impacted before deciding to change this setting.
The Ads section controls how Facebook can use your information in ads, and if Facebook will show you targeted ads on other sites.
Set "Ads based on my use of websites and apps" to "No" to stop other sites from sharing your interests with Facebook so it can show you targeted ads. If you want to stop these other sites from sharing this information with each other, click here.
Set "Ads with my social actions" to "No one," or your friends could start seeing your name attached to ads.
Finally, even though Facebook won't be getting information from other sources, it still uses your likes and what you post to target you with ads. Go under "Ads based on my preferences" to control what Facebook thinks it knows about you.
There are a few more sections of Facebook's Settings, but outside of "Payments" these don't have anything to do with security or privacy. Just pop into the "Payments" section to make sure you didn't add a credit card to Facebook at some point in the past. If so, you can remove it.
Privacy and security are well and good, but Facebook can just be downright annoying sometimes. Learn about one change you can make to your News Feed today that will make it much nicer to use.