I have my iPhone 8 and factory reset and it has an Apple ID but have no idea what it is

Sorry, but we don't know it either. It should be your email address unless you have changed it.

For Problems With Your Apple ID

1. Forgot iCloud Password
2. Forgot Apple ID
3. iForgot Password - Apple ID
4. iForgot UserName - Apple ID
5. Apple ID Password Change
6. Apple ID Name Change
7. Apple ID - Apple Support
8. Manage your Apple ID primary, rescue, alternate, and notification email addresses
9. About your Apple ID email addresses
10. Get help with Apple ID
11. Contact Apple for help with Apple ID account security - Apple Support
12. What to do after you change your Apple ID email address or password - Apple Support

Reset Security Questions

Contact Apple for help with Apple ID account security

If you forgot the answers to your Apple ID security questions - Apple Support

Starting an  online  chat with  Apple  Support

Apple Support using Twitter

You may need to reach Apple’s Account Security department. If you cannot find your country or are not able to call, then complete this form and send it to them.

Try using Apple's iForgot service. If it says they don't have sufficient information, you need to contact Apple's Account Security team. To reach them, click here and pick a method; if you can't use any of the ones listed, fill out and submit this form.

Activation Lock Problem

If you purchased the device second-hand, then it is useless without the Apple ID and password to which it is locked. If you don't have it, can't remember it or cannot get it, then the device is useless to you. Try to get your money refunded, if you can, or take it to an Apple store for an exchange provided they will help you. If you are the original owner, then take the device, a copy of your purchase receipt and identity proof to an Apple retailer where they may be able to assist you. For a deceased owner see How to request access to a deceased family member's Apple accounts - Apple Support. Note: there is no guarantee that anyone can gain access to the device.

About Activation Lock on your Mac - Apple Support.

Activation Lock - Turn off Find My iPhone.

About Activation Lock on your Apple Watch - Apple Support.

Turn off Activation Lock - Apple Support.

Need  to  disable  Activation  Lock  on an  iPhone  or  iPad?

See Turn off Activation Lock https://support.apple.com/en-us/HT201441. All possibilities related to iPhones, iPads, and iPods are covered here except the case of inheritance.

If you are the original owner:  If you have iOS 11 or later and your account is protected with two-factor authentication, use get help with a forgotten passcode or disabled device  to recover your passcode.  Otherwise, use forgot your Apple ID or your Apple ID password to recover the needed credential(s). If you can’t recover the needed credential(s), contact Apple Support and present your original purchase receipt for your device from an authorized Apple seller with the device’s serial number on it. You’ll need a photo ID too. If you can do neither, then the device is useless to you.

If you acquired your device second hand, you usually will need to obtain the needed password from the prior legal owner or have the prior legal owner sign out of iCloud; erase the device; and remove it from their device list. If unsuccessful, in the rare case your device came activation locked from an authorized Apple seller, then contact Apple Support and present your original purchase receipt for your device with the device’s serial number on it. You’ll need a photo ID too. If you can do none of the above, then the device is useless to you.

In either case, you can use the suggested support options below if you have the needed receipt. Alternatively, if an Apple Store is open in your area, then you can go there to deal with your problem. In this case, you can make a genius-bar appointment (https://www.apple.com/retail/geniusbar/) if you want.

Get a call from Apple support to help solve your problem using this

link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362  Be patient. Sometimes Apple phone support is not available.

Apple ID Support https://support.apple.com/apple-id

Apple Support Twitter  https://twitter.com/AppleSupport  There may be an hour or so wait.

Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169

Get Support: We’re here to help https://getsupport.apple.com/. Go through the options to find the best support option for you.

Return it to Sprint and ask for a refund.