Sorry, update of your iPad simply isn’t possible. Apple ended update support for your original (first generation) iPad in September 2012; it’s obsolete.
The final IOS release for iPad1 was iOS 5.1.1. It cannot be updated to any later major version of iOS as it lacks the minimum hardware requirements needed to run more recent versions.
Most App Developers have also dropped support for older devices and iOS versions preceding iOS11/12/13 - and have withdrawn older versions of their Apps from the Apple App Store. As such, usefulness and utility of older models are becoming increasingly limited - and in some cases, such as with iPad1, of little use at all.
If Apps that you need to use now have higher minimum iOS-version requirements, your only option is to replace your iPad with newer model. Of current models, even the entry-level iPad7/8 supports current iPadOS 14 - and has hardware specifications and capabilities that vastly outperform your original iPad.
Sorry, this is clearly not the news that you were hoping to hear.
I hope this information is helpful - if only in clearly stating the fundamental limitations of your current iPad and your potential ways forward.