Tiling - mastic, sealant or caulk - Tile Advice

[This_DIY_novice]

Total plumbing-tiling novice.

Our bathroom has been tiled. What should we use to seal internal corners and where the tiles meet the ceiling - mastic, sealant or caulk? I'm confused about the difference and have had varying advice.

Once it's sealed, can I cover the edges (ceiling, floor, internal corners) with edging, or is that not a 'done' thing?

Thanks