How could I can update my iPad 4 with latest iOS 13

You don't.

A 4th gen iPad cannot be upgraded beyond iOS 10.3.3/10.3.4 for WiFi & cellular data models.

A 4th gen iPad is a NEARLY 8-year old device, now!

These older iPad models are too old, now, too underpowered and completely incompatible with any of the current and future versions of iOS/iPadOS.

Sorry, but it is what it is, today, in the year 2020!

These old 8 and 9-year old iPad models will soon be rendered completely OBSOLETE by the end of 2020!

Here's why and what you will need to do about it in 2020!

Tap and read my link below for my additional info about your old iPad model.

If you own OLD 8 and 9 Year Old iPad mo… - Apple Community

Sorry & Best of Luck to You!

It's time to replace that 8 year old iPad, with a more modern iPad capable of running the now required 64 bit software for iPadOS 13. Your device is too old, too under powered, no longer supported and not able to run the newer software.

An iPad 4 isn't capable of running 11 or above.

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