I can’t update ipad

Return that iPad and get your money back and get another iPad that supports either iOS 12 or iPadOS.

iPad 2, 3, 4 and 1st gen iPad mini models are 7 and 8 year old devices, now that can no longer be upgraded.

All these iPad models are too old, now.

Look at

iPad Air 1 or 2 models.

iPad Mini 2, 3 or 4 models.

iPad 5th, 6th or 7th gen models.

if it's the ipad 2 then 9.3.5 is the newest version it support https://en.wikipedia.org/wiki/IPad_2

Sorry, but no. Both the iPad 2 and 3 are stuck on 9.3.5 (9.3.6 for cellular). These iPads are very old, they are from 2011 and 2012. Better off buying a new device.

Even the 4th gen iPad from 2012 is stuck on iOS 10 and the first gen iPad Air from 2013 is stuck on iOS 12.

Please get a new device if you want to use those apps.