How can I hide the air conditioner on my balcony?

Here are some great options! Whatever you do, make sure it has proper air flow. Otherwise it will overheat and burn out prematurely and could void any warranty you may have.

https://www.countryliving.com/gardening/g4475/hide-air-conditioner-unit/

https://www.pinterest.com/pin/537476536760080597/

https://www.pinterest.com/pin/214624738463226051/

build a box to fit around using 2x2's and privacy lattice, you can then use it as a table or for plants etc. it can be easily lifted off for servicing if need be

You don't state what kind it is. Free standing or wall unit. If it's a free standing unit make sure you have space around and the top for air flow. Do not fully cover any of the openings.

Screen - Plants - furniture?

If the a/c is a one end of the pitch, you only have to hide the side you see the most. A folding screen could block it off. You can make a cheap folding screen out of a tall piece of fiberboard or foam board, painted any color you choose. If you have a real or artificial tree to set on one side of the a/c, that’s another side blocked. Paint only the metal frame of the unit to blend with the house. Don’t block any of the vents or filters. Set a potted plant on the floor beneath the unit—one that likes lots of water. And look around—you can probably see lots of a/c units, but none will look prettier than yours. ☺️

I would surround it with plants or accessories. But make sure you aren't covering up the vents by giving the AC enough space to function.