If you don’t know the account credentials, this could be hard thing to pass this step. You have to login to the Apple account that was previously used in the device and then you can start using it.
Devices running iOS 7 and later comes with the feature called “Find my iPhone”, actually this service protecting the device from unauthorised usage like if its get stolen or The previous owner of the device forgot to remove their Apple ID account from their device before selling it or gifting to someone, in such cases If you reset your iPhone or iPad or you have to set up it from scratch: as one of the checkpoint you need to activate your device with an Apple ID and a password that was previously signed in on the device.
IPad, iPhone Activation lock will mostly happen on second-handed, used phones and stolen phones.
