i have seen bitcoin address starting with 3 instead of 1 but i don't know it was possible to generate such address in bitcoin core qt wallet
there should be a complete step by step tutorial for this
I didn't know about this feature either , since It not in the Graphic Interface User on Bitcoin Core but only available if you use commands (a lot of features work with commands only) .
If you want to make an adress that start with 3 then just look what fsb4000 said above . I made one succesfully with his help
~ Madness.