What Game Size is 9:16 and How do i add text stroke?

im trying to make a mobile game with the ratio as 9:16, but i dont know what dimensions i should make my game size. I also need help with adding stroke to text

its basically resizing the game world size to any multiple of 9 and 16

Idk if this helps but I know that 4:3 ratio is the Flowlab cover size and it is 16 by 12 flowlab grid spaces