how to erase ipad without apple id password

I suspect you are encountering this: Apple has two related features, Activation Lock ( Activation Lock for iPhone, iPad, and iPod touch - Apple Support ) and Find My ( iCloud - Find My - Apple ), which are designed to prevent anyone else from using an iPhone, iPad, or iPod touch if it's ever lost or stolen. Deactivation of either requires knowing the Apple ID and password that set the feature, or by placing a special request to Apple to reset the device. This Apple ID information essentially defines the current ownership of the device.

Click on this link to learn how to remove Activation Lock --> How to remove Activation Lock - Apple Support

or this one for disabling Find My if activation lock has not yet engaged --> Turn off Find My on your iPhone or other devices - Apple Support

If you do not know the required information, get the owner of the account to remove the lock (the section: "If you no longer have your iPhone or iPad" in: What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support ). The device is otherwise useless to you. If the owner is unknown and has not provided contact information as a message showing in the login screen, there is no way to contact the owner unless the person who gave you the device knows them.

Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. This is done online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not provide many details in the article as to what is acceptable proof. Prior to this official service Apple typically required the original receipt* issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the first owner who does this, or a descendant with legal proof of ownership transfer).

*Apple recommends you keep your receipt after you buy an Apple device. --> Keep your receipt after you buy an Apple device - Apple Support

Also of intereset: Apple Business Essentials --> Intro to Apple Business Essentials - Apple Support

Apple Business Essentials includes all the features of Apple Business Manager and more. Apple Business Essentials is one complete subscription that seamlessly brings together device management, 24/7 support, and cloud storage so your small business can easily manage every employee’s iPhone, iPad, Mac, and Apple TV (that your organization owns)—every step of the way. Apple Business Essentials is currently available only in the United States."