I got an email that said, "We've found a missing field in your profile" So, how do I find the missing field?

That might just be a marketing email.   Did you already e-file?  Was your return accepted by the IRS?  TT is sending out a lot of marketing emails to get people to file.  Many users have old accounts that trigger those emails.   If you already filed and your return was accepted you can ignore that email.