Enable minecraft pvp?

I'm playing with my sis and want to split screen pvpn. Xbox bedrock version but nowhere I can activate it, it was never like that…

If you leave and then edit the world from the menu there's a point called "friendly fire" or something like that. You have to change it and then pvp works

Alright thanks. Does that mean it has to be on or off?

Must be on

Did it work?