Simplify the following text for a Grade 9 native English-speaking person.
Original: Internet message access protocol ( commonly known as IMAP ) is one of the two most prevalent Internet standard protocols for e-mail retrieval , the other being the Post Office Protocol ( POP ) .
Simplified: Internet Message Access Protocol ( or IMAP ) is a set of rules that e-mail programs use to download email . Another protocol which does the same thing is called Post Office Protocol .