Why my phone it's not charging

That’s like saying; “My car doesn’t go; why doesn’t it?” There are many possible reasons, here are a few:

• Defective power source
• Poor quality power source
• Defective Lightning cable
• Dirt in the connector on the bottom of the phone
• AC power source where it is plugged in is intermittent
• Water damage inside the phone
• Defective battery
• iPhone built in charger was damaged from using it with a cheap cable or cheap power source.

Basic troubleshooting is to try a different power source, and different cable, clean the connector on the bottom of the phone with a toothpick, and try with a wireless charger.

You can try to buy a wireless charger. Wireless charger