How can you teleport with a command block in Minecraft?

I would like to make a command where you can teleport from A to B. How can you best do that?

Simply enter [coordinate or player] in the command block / teleport [player].

/ teleport @p (coordinates)

But it all depends on what you want to do. @r would be an option if you're teleporting any random player. @a all players. Names are also possible.