Explain The Difference Between A Logline And A Synopsis

You are about to pitch a screenplay and two terms keep appearing as if they mean the same thing, which they do not. This explains what each document is for, how long each should run, and who expects which one at what stage. For first-time screenwriters about to approach producers, agents, or competitions.

I am about to pitch a screenplay and keep seeing 'logline' and 'synopsis' used as if they are interchangeable, and I am not sure they are. Explain the difference between the two: what each is for, roughly how long each should be, who reads each one and at what stage of the process, and what happens if I send the wrong one to the wrong person. Use my screenplay's genre, {GENRE}, as the example throughout.