Q: Text messages stopped forwarding to my Mac and I didn't hange settings. When I try to reset text forwarding my Mac doesn't come up as one of my devices. How do I get texts back to forwarding to my Mac messages app?

"Text forwarding"?  There is no such capability, but there are some things closely related ...

You may well mean using Handoff, described here:

OS X Yosemite: Pick up where you left off with Handoff

... or you may mean linking your iPhone's telephone number to the Mac's Messages app described here:

iOS and OS X: Link your phone number and Apple ID for use with FaceTime and iMessage - Apple Support

Set up text message forwarding

To receive and send SMS and MMS messages on your Mac, your iPhone needs iOS 8.1 or later, and must be signed into iMessage with the same Apple ID as your Mac.

1. On your iPhone, tap Settings, then tap Messages.
2. Tap Text Message Forwarding.
3. Tap to turn on Text Message Forwarding for your Mac.
4. On your Mac, open Messages.A six-digit activation code appears.
5. Enter this code on your iPhone, then tap Allow.

You can now send and receive SMS and MMS messages on your Mac.

Apologies ... modular747 is correct.  My oversight.

I Don't have a "text message forwarding" setting. Any thoughts on why?

See the various requirements here:

Use Continuity to connect your iPhone, iPad, iPod touch, and Mac - Apple Support

They include:

• Another iPhone or iPad or iPod Touch using at least iOS 8.1; or
• A Mac using OS X Yosemite; and
• Having set up Continuity as described in the article

Text message forwarding require iOS 8.1 or later and OS X 10.10 or later.

I had this problem too, so I powered off my iPhone and powered it back on. When it came back up and I checked the iMessage settings, the "Text Message Forwarding" setting was there.

I've done this, but when I open messages I don't get a 6 digit code...I have current updates on laptop and phone