How do I delete my number from iMessage on send and receive from my iMac? When I go to settings, iMessage does not show up under anything and I cannot access iMessage settings straight from the iMessage icon.
Open the Message app first before doing the following:

To remove your phone number from the Messages app in OSX, you need to change your Messages preferences: Command+,

In the Preferences box, click Accounts, select your iMessage account on the left, and uncheck your phone number on the right.