Contraception refers to the techniques used to prevent pregnancy.
If you want to prevent both pregnancy and STI transmission, either don’t have sex* or use a complete barrier, like a condom.
Popular forms of birth control include:

Watch this 13 minute video from Crash Course to learn how birth control works. Yes, this is the same video that’s in Contraception 201, but it’s packed with great information and is worth re-watching!