You can't get everything, but you can:
1. Delete all of your past social posts and delete unused accounts so they aren't used against you
2. Request takedowns of your personal info on the People Search sites like Spokeo
3. Delete any accounts you don't want to have
4. Moving chats to encrypted platforms
I can't tell you enough how importing it is to control how people see, share, and store your personal data. Once it's out of your hands, people can take is and use it any way they want. The article at the link isn't comprehensive, but it's a good start.