iPad not in finder

On a Mac running macOS Sierra, you need to use iTunes.

Starting with macOS Catalina, the Finder replaces iTunes to sync your iOS device with your Mac.

See also this support page:--> Use the Finder to sync your iPhone, iPad, or iPod with your computer - Apple Support

Regards

Giulio

Welcome to Apple Support Community!

First troubleshooting step I would recommend, is updating to the latest version of macOS that is available for you.

If your computer doesn't recognize your iPhone, iPad, or iPod. https://support.apple.com/en-us/HT204095

> Make sure that your iPad is on and unlocked while plugged into the Mac.

> Check Mac and iPad for a "trust this device" message. Click Trust

> Restart iPad and Mac.

Hope this helps ;)