In an email greeting "Good morning" does the word "morning" need to be capitalized? Is it Good Morning or Good morning?
1. If you search Google images for "good morning" you will discover that the following occur on greetings cards:
However I did not see an example of "Good morning" on a greetings card.
2. If you are writing dialog, only the first word should be capitalised, e.g.
"Good morning!" said John.
"Good morning, John!" I replied.
3. If it is the first line of an email, my choice would be, e.g.
Good morning! Thanks for those photos you sent me ...
but I don't think it would be incorrect to say:
Good Morning! Thanks for those photos you sent me ...
I would say that it is a matter of style.