See: If you forgot your Apple ID password https://support.apple.com/en-us/HT201487
You also can use Having trouble signing in/iForgot https://iforgot.apple.com/password/verify/appleid
And you undoubtedly will need to see If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485
Before trying to answer your security questions is very important that you think about your questions and their answers carefully and try to recall all details you can. If you don't answer them correctly enough, then you easily can lose control of your account.
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See If you forgot the passcode for your iPhone, or your iPhone is disabled https://support.apple.com/en-us/HT204306
The instructions are essentially the same for an iPad and iPod touches. “If you enter the wrong passcode too many times, you’ll see a message that your device is disabled. If you can’t remember your passcode, you'll need to erase your iPhone, which deletes your data and settings, including the passcode.”
If you backed up your iPhone, you can restore your data and settings after restoring your iPhone. If you never backed up your iPhone before you forgot your passcode, you won't be able to save the data on your iPhone. Follow the steps below to remove your passcode.”
Next, remove your passcode (see the document for the steps). Then, restore you phone of your computer (see the document for the steps).
“If you can't update or restore your iPhone using recovery mode, or you can't use recovery mode because of broken or stuck buttons, contact Apple Support. Then follow the steps to set up service for your iPhone.”
