I have no signal on my new iPhone 13

Check the range of the mobile network, see this Apple article:

If you see No Service or Searching on your iPhone or iPad

If you see No Service or Searching on your iPhone or iPad - Apple Support

Contact your carrier 

Issues with your carrier or account might affect your service. Contact your carrier to:

• Verify that your account is active and in good standing.
• Make sure that there are no outages in your area.
• Check that your device isn't blocked from receiving cellular services and is set up with the right data plan.

Get more help

• If your carrier confirms that there's no issue with your account or network, but you still can't connect to a cellular network, contact Apple Support.

Hello,

You can use this guide to help resolve your "no service" issue.

Thanks for reaching out!

-Drake