How do I change HP and MP limit in hex editing?

I have Hex Editor but what will I do to change the HP and MP limit/cap from 9999/999 to 32767 or 65535 in FF6 SNES?

There's a lot to consider. You'd need to remove the capping for various calculations in bank C2 and somehow adapt the MP / HP display in menus that have little if no room.

It's a whole lot of trouble and requires good knowledge of assembly as well as fairly deep familiarity with FF6's code. It can definitely be done, but personally, I think it's more trouble than it's worth.