How can I add more storage on my IPad

You can't. Storage was fixed at purchase and there is no way add memory to a device. If you need space you have to delete things your don't need or use, such as Apps, Photos, Music, Files, Messages, Email, etc.

Next time you buy a new iPad, make sure you get one with enough memory to meet or exceed your storage needs.

Read above. You CANNOT add storage to an iPad. That means, NO.

You can't.

You have to manage the storage your iPad came with when you bought it.

Buy storage for my iPad