The document lists and defines 10 common email acronyms. It explains what each acronym stands for and how it can be used in email communications to save time or reduce unnecessary responses. Some examples provided are PRB (Please Revert Back), LET (Leaving Early Today), NRN (No Reply Necessary), and TL;DR (To Long; Didn't Read). It aims to help readers sound less "dumb" by familiarizing them with acronyms frequently used in work emails.