i logged into the wrong email on imessage on my MacBook Air and cant find a way to change it

Hello -vaud,

To change which email you use with iMessage, first:

• Open the Messages app on your device.
• Go to the menu bar and select Messages and then Settings (or Preferences if using macOS Monterey or later).
• In the window that opens, you will see "@ iMessage"; select this.
• Now you will see "You can be reached for messages at:" and there will be options for which email address you want to use.
• Select your preferred email address by clicking on the box next to the email. You can deselect the one you do not want to use.
• You can also change which email address will be used to start a new conversation by looking under the "Start new conversations from:" section.
• Once again, select the preferred email.

These articles might help for further information:

Set up iCloud for Messages on all your devices - Apple Support

Messages User Guide for Mac - Apple Support

Also note in this guide:

I hope this helps. Have a nice day.