How do you get jtag if you cant do it yourself?

i dont exactly get what is to be done to jtag yourself but is there any other way i could get my xbox jtagged

If you can’t Jtag it yourself pay someone to do it for you. Other than that your only other option is to buy one already modified.

must you need jtag for any sort of bo2 fun lobbies?

If by BO2 fun lobbies you mean modded lobbies, yes if you want to host one yourself. Otherwise no, you can join a modded lobby hosted by someone who owns a JTAG.