Repair hole in ceramic floor tile

Replacing a single tile is a tricky job and is likely to leave you with a situation where it is obvious what has happened. Even if you can match the tile perfectly, a new one and the new grouting are going to be very obvious for a long time - many months and possibly even a couple of years.
You should be able to get some kind of filler which will fill the hole and then match the surface colour as necessary. Any DIY store should be able to advise you.
Only try an actual replacement after it's clear that nothing else works.
Good luck.