How to Post a Rent Increase in an Expensive Neighborhood - California

[Deborah Vaupen]

I am raising my rent for the first time, and learned I can mail it but I have to also "Post" it.  How do I post in an expensive/nice neighborhood?  It seems very tacky to just tape a letter to a door.  Or do I put it in an envelope and tape to the door? What is the actual way to do it in a nice neighborhood?