To remind yourself to follow up on a message, you can add a follow-up flag. A flag gives you a visual cue that you want to return to that message later. In the message list, flagged items display the 
symbol.
Pinning a message moves it to the top of your inbox so it's easy to find later. A pinned message is indicated by a 
symbol.
Flag a message
-
In the message list, hover over the message to see the flag option.
-
Select
to flag the message. -
Select
to unflag the message.
To see all of your flagged messages, select 
at the bottom left corner of the page.
Pin a message
Note: To pin a message or see pinned messages, your inbox must be sorted by date. Select Filter at the top of the message list to change how your inbox is sorted.
-
In the message list, hover over the message to see the pin option.
-
Select
to keep the message at the top of your inbox. -
Select
to unpin the message.