how can i add insurance to my ipad that was not purchased through tmobile

Thanks for reaching out Anbonilla,

It sounds like you are looking to purchase an AppleCare+ plan. We can help.

You can check out the article, Buy an AppleCare plan, for more information:

In most countries and regions, you can buy AppleCare+ within 60 days of your device purchase. In Japan, you can buy AppleCare+ within 30 days of your device purchase. In China mainland, you can buy AppleCare+ on your device within 7 days of your device purchase or in an Apple Store within 60 days of your device purchase. (At the Apple Store, you'll need to bring your proof of purchase, and we'll inspect the device.)

Buy an AppleCare plan on your device

1. On your iPhone or iPad, open Settings. Or on your Mac, choose the Apple menu (), then choose System Settings.*

2. Go to General > About.

3. Tap AppleCare+ Coverage Available. If you don't see AppleCare+ Coverage Available, check to make sure that your device is eligible.

4. Follow the onscreen instructions to complete your purchase. You can see the price of the AppleCare plan when you follow these steps.

Hope that helps,

Take care.