Q: iMessage (phone number) not an option in messages accounts

I can't seem to get Messages on my mac to link to my phone number to send and receive iMessages. I have done it before and it was quite simple but now when I try to add it, there's not even an option in my accounts pane for adding a phone number. I have signed in and out on my phone and computer and searched for an answer or similar problem but haven't seen much. HELP! Below is a screenshot of what my messages/preferences/accounts looks like. I can't figure out where on here to set up my phone number. Thanks in advance for any help!