A factory reset/restore may fully reset the iPad and remove an unknown passcode - but this may not be enough to recover use of the iPad.
If the device is not centrally managed by an MDM platform and you permit your staff to configure the device with their own (possibly private) account credentials to set-up and use devices, there is a very real risk that you’ll lose the ability to access or use the device. If the staff member has left your organisation without properly unlocking the device, as a business you might totally lose access to (and use of) the unmanaged device. If you don’t have robust exit procedures, this is a real risk.
If the device is disabled or Activation Locked, you will require your original purchase documentation that proves ownership - usually the sales invoice. Documentation must clearly show the Serial/IMEI number of the device. With this documentation, Apple may at their absolute discretion assist with unlocking.
A forgotten or unknown iPhone/iPad passcode cannot be recovered - and neither can it be reset or modified from another device. If you see a waiting period you can wait and try again to input the correct Passcode; otherwise, the iPad must be restored.
You may find this support page to be helpful:
If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support
iPadOS 17 or later with a forgotten Passcode
If you have changed your passcode in iOS/iPadOS 17 and later - and have since forgotten the new Passcode - you may be able to recover access using your previous Passcode. Passcode Reset gives you 72 hours to use your old Passcode to access your device; when you access your device in this way, you must change your passcode again immediately:
Temporarily use your old passcode when you forget your new passcode on iPhone or iPad - Apple Support
If you cannot use the new Passcode Reset feature, you must use another method.
iOS/iPadOS 15.2 or later with a forgotten Passcode
Apple has introduced a procedure with which to reset an iPad or iPhone with a forgotten Passcode - allowing you to use your AppleID and associated Password to reset your device.
How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support
You will be able to restore data from a pre-existing iCloud backup without the use of a computer, but will require a PC/Mac to restore data from an iTunes backup.
iPadOS 15.1 and earlier - and all devices that are Disabled
If your iPhone/iPad indicates that it is disabled/unavailable/locked-out, or you have forgotten your iPad passcode, you have no alternative other than to follow this process:
If you’ve forgotten the passcode on your iPad, or your iPad is disabled – Apple Support
You’ll need access to either a Windows PC (with iTunes for Windows installed -or more recent Apple Device App) or a Mac computer (with iTunes or Finder - as appropriate for the installed version of macOS).
Download and use iTunes for Windows – Apple Support
Update to the latest version of iTunes – Apple Support
Apple Devices App (Windows PC):
https://apps.microsoft.com/detail/9np83lwlpz9k?hl=en-ms&gl=MS
Use of a PC or Mac is unavoidable. If you don’t have access to a suitable computer of your own, that of a helpful friend or family member will suffice. Alternatively, the technicians at the Genius Bar of your local Apple Store will be delighted to assist:
Genius Bar Reservation and Apple Support Options - Apple