Auto-population Troubles

Good Morning Excel Experts,

Hope this thread finds you well. I am trying to form an Excel Worksheet that will automate comments in one Column based upon what letter is entered into Column C. The formula I have so far is:

=IF(C2="D","Account Requiring Assist Code Adjustment",IF(C2="E","Adjust Source Code",IF(C2="F","Adjust LM Counselor",IF(C2="G","Adjust Plan Type",IF(C2="H","Email Assigned Rep","")))))

However, I am looking for a non-VBA way to have it where the user can enter multiple letters into Column C and have multiple comments appear.

For Example, if Column C had D, E & H entered. The comments would appear as, “Account Requiring Assist Code Adjustment,” “Adjust Source Code,” and “Email Assigned Rep.”

Would the entry method in Column C to obtain multiple comments need to be entered with a comma and no space? A semicolon and no space? A comma with a space?