I bought iPhonex 3 years back and till nowI face mobile network issues . I changed my sim, service providers but no network on the earth supports this phone

How did you come to own this iPhone X; was it bought new from Apple/Apple Reseller or from a Mobile network or even used via one of those resellers such as eBay ?

I ask because what you are describing is the result of a network LOCKED phone.

That is to say an iPhone sold by a mobile carrier for exclusive use on their network subject to subsidies.

If that is the case you can't use this phone with another network SIM, unless unlocked from the original carrier and with the original SIM card onboard and that by the original owner.

If you can get to the Home Screen

Tap the following

Settings/General/About -Scroll down and look for Network Provider Lock - this will have the name of the carrier or otherwise NO SIM restrictions if unlocked.

If the phone is locked and YOU aren't the original owner afraid you have a brick and can't use it .

Did you use a sim card from the carrier you had when you first bought the phone? What is the exact error message that you get with a SIM card? Are you the original owner of this phone?