Why my phone is not charging ????

I have no idea. My car doesn’t go; why doesn’t it?

In other words, you need to provide a lot more information before anyone can address your issue. Starting with:

• Are you using a wall power adapter or a computer?
• Is the cable an Apple cable or at least a cable certified as Made for iPhone?
• Have you tried a different wall adapter?
• Have you tried a different cable?
• Have you inspected the Lightning connector on the bottom of the phone for impacted dirt that could prevent a cable from making contact?