Apple - My ex-girlfriend uses my Apple ID to log in to her iPad. Do I have to give her my Apple ID password to reset it?
Don’t just give the password - that gives full access to your account - she could change the password on you... Make it that you enter the password and reset... Either meet or she sends you the iPad...
As discussed elsewhere in the answers, it is generally not advisable to simply share your Apple ID password with others.
Also, having Two-factor authentication enabled provides an extra layer of protection (by notifying you with location and device type of where the login is attempted), and makes any unintended login attempts moot.
Alternative to Sharing Apple ID Password
Generally friends/family exchange Apple ID password to get access to purchased apps, music and movies. A much better alternative than sharing password is to use Family Sharing feature which allows purchased content to be shared.
For more information refer to the linked Family Sharing homepage and the Apple Support article:
Family Sharing - Apple
Family Sharing - Apple Support
Family Sharing is recommended, because unlike sharing password, it doesn't give unfettered access to your Apple account while letting you share what you may need to share.
Coming to the original question, yes it's required to enter Apple ID password and sign out before resetting an iOS device. This is done to discourage any unintended reset attempts. Additionally, Find My iPhone needs to be disabled too (if enabled) when resetting an iOS device.
- Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac
As very nicely and cautiously noted by @SolarMike, sharing the password may be potentially dangerous unless you trust the person with it. It is advisable to get the iPad in person, enter the password, sign out and reset it yourself.
Once signed out, check if the device is removed from your account by going to iCloud settings on any one of your other iOS/macOS devices or by going to iCloud website.
As a precautionary measure, you should also changed the password once your ex-girlfriend's device is removed successfully from your account.
Also, as discussed above, consider leveraging Family Sharing feature in future.
Important Note
It's crucial to note on this occasion, that you enable Two-factor authentication (if not done so yet) for your Apple ID. It helps in tracking and identifying unintended login attempts using your Apple ID. Having Two-factor authentication requires someone with access to your password to approach you to get the code, thereby ensuring security of your account.
Any login attempt is notified to you on your trusted device(s) with information regarding device type and location where the login is attempted. For more details, refer to the Apple Support article:
- Two-factor authentication for Apple ID
The only way to do it is do it yourself. You need to log out, log out of iCloud, and turn off "Find My iPad". Then she can create her own AppleID and log in with it.
I'd recommend to make an appointment at an Apple Store where you both meet, then you will have someone there who (a) goes through the procedure without getting anything wrong (I can't quite guarantee that my instructions are 100% right), and (b) who can make sure that nobody does anything nefarious (like making sure all you do is entering the password, and making sure your AppleId is gone in the end), and who (c) can help her setting up her own AppleId.