Condoms are the only kind of contraception that is prevents pregnancy and provide protection against STIs. Condoms are a thin, fitted tube worn over the penis and act as a barrier and prevents the exchange of fluids. It is easily accessible, cheap and widely used. Condoms are 98% effective if used properly.
Note: Silicone based lubes are not compatible with condoms as they can break. It is better to use water based lubricants with latex condoms.
Sources:
https://my.clevelandclinic.org/health/drugs/9404-condoms
https://www.nhs.uk/conditions/contraception/male-condoms/
https://www.webmd.com/sex/birth-control/birth-control-condoms