On a bicycle tire, there are mainly three types of valves:

Presta valve

or French valve

Thinner and narrower than other valves (6 mm in diameter compared to 8 mm for the others).
Has a knurled nut on the top that must be unscrewed to inflate it.
Offers better inflation accuracy and allows higher air pressure.
More common on road bikes and hybrid bikes.

Schrader valve

or American valve

Wider and thicker than the Presta valve.
Has a tip similar to that of car tire valves.
Does not require any tools to inflate it, a simple air compressor is enough.
Less precise than the Presta valve and cannot achieve such high air pressures.
Most common on mountain bikes, city bikes and children's bikes.

Dunlop valve

or English valve

Less common than Presta and Schrader valves.
Similar to the Presta valve, but with a different closing system.
Less efficient than Presta and Schrader valves.