Apple ID
I used a work email on my apple ID. I no longer work there and I cannot remember my password
iPad Air 2 Wi-Fi
Is the email address still a valid email address? If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.