How much time will it take to backup a 256gb iphone X to a pc? I am taking more than 4 hours, Is it okay?

We need more info. Examples:

• Is the progress bar moving? How far along is it?
• What version of iTunes are you usin? (Do not say “the latest”.)
• Has the iPhone been backed up before?
  • to iTunes?
  • to this computer?
• What version of iOS?

If you plugged your iPhone into a USB port and are using iTunes, the backup should take a few (perhaps no more than ten) minutes.