I keep seeing people posting on social media that they have been hacked. Hacked is when someone gets into your account without your permission, and can post and change settings. This can happen, but it is not common.
Far more frequent is being cloned. This is when they don’t have your password or access to your account, but create a copy of your profile, often using your profile pic and publicly available personal information. They do this to make it easier to scam your friends. The more friends you have, and the more personal information anyone can see, the more attractive your account is to cloners, because that gives them more chances to rip people off.
You can’t stop this happening. But you can reduce how attractive your profile is to cloners by making your personal information and friends list private. If they can’t see your personal information it is harder for them to fool your friends, and if they can’t see who your friends are, they won’t know who to send friend invites to.