iPad not charging

Are you using the correct charging cable? Lightning and USB-C connectors are fundamentally different - and are not interchangeable.

If you are using the correct charging cable - check for foreign objects, fluff, lint or other dirt that may be obstructing the charging port of your iPad. Consider using a plastic or sharpened wooden toothpick to carefully dislodge any material that may be blocking the charging port - taking care not to damage the delicate electrical contacts.

If the problem remains unresolved, you would be best advised to seek help from the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to provide assistance:

Genius Bar Reservation and Apple Support Options - Apple