The free warranty of ipad is from purchase date or from activation date

The warranty period starts from the date of purchase.

If you buy an Apple device (iPhone or iPad) from official channels (Apple Online Store, Apple phisycal Store, Apple Authorized Resellers) Apple is automatically informed of your purchase.

If you do the same from other channels or gray market, I think that Apple is not informed of your purchase AND the warranty peroiod might have started when those "channels" bought the device from Apple directly, or from other authorized Resellers.

Regards

Giulio

To clarify, Apple may use the date of first activation to estimate the start date of your Apple Limited Warranty. However, should you make a warranty claim, you will be required to provide your sales invoice to prove warranty entitlement. In most countries/regions, your warranty begins on the day of purchase.