My iPhone X carrier shows lock ,how can it unlocked

If you are locked to Sprint you have a problem, they don't exist anymore, they are part of T-Mobile. And their policy was you had to use their service for 6 month before they would allow you to unlock the iPhone. You can try to contact T-Mobile and see if they can help you or you can return it where you purchased it and get your money back.

https://www.t-mobile.com/support/devices/unlock-your-mobile-wireless-device/

Contact your carrier, ask them what their unlock policy is and if you qualify.

That would depend on the carrier it is locked with.

Click on the link, the blue letters.