The subject corresponds to the name of the mail under which it is found in lists and search queries. Depending on the mail template used, it may also be listed in the mail itself.

1. If you create a mail from another record or if you use a template, the subject is often already prefilled.
2. Enter a custom subject in the input field or select an entry from the expandable picklist. Add new, frequently used subject texts by clicking on Edit list.
3.  Save the new mail under the recipient account.