Bullnose trim is a common option for adding trim to tile. It's not the only one, though, and you might be better off with one of these alternatives.

The shower door was clearly installed incorrectly. Typically, the bottom of the framing rests on a threshold made of tile or stone that is deep enough to extend beyond the frame inside and outside ...

The added materials required will be 8 bullnose tiles to finish off the edges. Step or Seat — Shower seats are very popular but take up a lot of space in a tub to shower conversion.