How do I update my iPad to IOS 13

See this support article:--> Update your iPhone, iPad, or iPod touch – Apple Support

But before proceeding, you should identify your iPad model, using these instructions:--> Identify your iPad model - Apple Support, and check if your iPad supports iOS/iPadOS version more recent than the one currently running on it.

Find it out, then let us know the exact iPad model.

Thanks and regards.

Giulio

A little hard to help/advise you when you provide little to NO useful information about your iPad.

Here are my questions to you.

Can you, please, confirm what year and model iPad do you have/own?

The “A” model number can be found on the aluminium back of your iPad, in very small print, right under the larger bold print “iPad” on the back of the iPad.

What iOS/iPadOS version is this iPad, currently, running?

What is the rated, internal data storage space/capacity of your iPad model and how much of this free, internal data storage capacity is left inside of your iPad model?

All of that additional info can be found in the Settings app, General settings panel, About.

Please try to make an attempt to answer all questions asked.

Thank You.