The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
You may either omit or include the comma after greetings like “Hi” and “Hello” in informal email salutations, depending on preference.
Use either a comma or a colon after a greeting. The colon is preferred in business or other formal communication in U.S. style.
Various phrases can begin an email, depending on formality (dear So-and-So, hi, hello, good morning). Using an appropriate salutation can set the right tone for your correspondence.
Don’t capitalize greetings like “good morning” except at the start of a sentence. Capitalize all words in an email salutation if it stands alone but only the first word if followed by a name.