HELP i dont know how to remove it! i want to sell my phone and don't want any information of mine left on it, and i am told i should remove the SIM card, except i can't find it and don't what to do!

If it's not possible to remove the SIM card, what else can i do to ensure that my personal info is not sold with the phone? thank u!

the wildcard does not have a SIM card virgin mobile has digital service(i think thats what it is called)