iPhone X warranty

At this point you probably can't.

You can buy Apple Care+, which extends the warranty to 2 years, within 60 days of having purchased the iPhone. If its been more than that, then there's no way to extend the warranty anymore.

You can check your local insurance companies or your credit card issuer to see if the have a warranty or coverage option for personal electronic devices.

You had to do that in the first 60 days.

You're device is too old now.

If it's been more than 60 days since you purchase it, you can't.