Hello. In my i phone XS Max my face id is not working. What can i do?

What trouble shooting steps have you taken? See this article:

If Face ID isn't working on your iPhone or iPad Pro - Apple Support

If nothing there helps, contact Apple. They can do remote diagnostics.

Genius Bar Reservation and Apple Support Options - Apple

tarun208 wrote:

How can I fix that ? Any suggestions? Please

What trouble shooting steps have you taken? See this article:

If Face ID isn't working on your iPhone or iPad Pro - Apple Support

If nothing there helps, contact Apple. They can do remote diagnostics.

Genius Bar Reservation and Apple Support Options - Apple

Sent to Apple for inspection, it may look good on the outside but inside something is wrong.

you also can send to a nearby county with a apple store

start here: https://support.apple.com

Ever had the screen replaced or did you put on a screen protctor?

That means your Face ID is broken