If my iPad is plugged into someone else's computer will the be able to access my information with my passcode or do they need my Apple ID also? I

Hello C. Irving,

You can only sync your iPad with computers that are authorized with your Apple ID.

Manage your associated devices in iTunes - Apple Support
https://support.apple.com/en-in/HT204074

You can associate your Apple ID with up to 10 devices, with a maximum of 5 computers at any time. Each computer must also be authorized using the same Apple ID. You don't need to authorize your iPhone, iPad, or iPod touch.

After you associate a device with your Apple ID, you can't associate that device with another Apple ID for 90 days.

Authorize your computer in iTunes - Apple Support
https://support.apple.com/en-us/HT201251

If you want to share music, you can do it with Home Sharing using the same Apple ID and wireless network, or by gifting items from the iTunes Store with others.

How to share music and video with iTunes - Apple Support
https://support.apple.com/en-us/HT201779

Cheers,

- Judy

Syncing with someone else's iTunes will erase all content that was synced to your iPad using your computer and iTunes.