i got a new iphone (13X Pro) and my sleepwatch app no longer gets info from my watch about my nights sleep. I think from what i can find i need 2 part authentication but i cant for the life of me figure out hot to turn it on/set it up?n

Inside the link I provided is an entire section on how to set up two-factor authentication. This is what is in the article:

Set up two-factor authentication for your Apple ID

You can follow these steps to turn on two-factor authentication on your device. Learn more about the availability of two-factor authentication.

Turn on two-factor authentication on your iPhone, iPad, or iPod touch

1. Go to Settings > [your name] > Password & Security. 
2. Tap Turn On Two-Factor Authentication.
3. 
4. 
   
5. Tap Continue.
6. Enter the phone number where you want to receive verification codes when you sign in. You can choose to receive the codes by text message or automated phone call.
7. Tap Next.
8. Enter the verification code to verify your phone number and turn on two-factor authentication.

You might be asked to answer your Apple ID security questions.

See this --> Two-factor authentication for Apple ID - Apple Support

Not sure why you don't get the turn on 2FA option. Use the Get Support button at the top of this screen to reach out to Apple directly for help.