Please do not confuse project dependent mail templates aka Project Mail Templates (tied with particular issue type) with Post Function Templates.
The easiest way to distinguish between them for an ordinary JIRA user, is that by default to access edition, or creation of Post Function Templates, one needs to be in a JIRA admin rank. Such high privileges are not needed to access Project Mail Templates.
Please do not confuse project dependent mail templates aka Project Mail Templates (tied with particular issue type) with Post Function Templates.
The easiest way to distinguish between them for