Please clarify you question, as thunderbird does not use a password for itself, other than the optional primary password. Passwords for your accounts are at settings>privacy&security

When I went to export to add thunderbird to my phone it asks for a password. I have five different email addresses, so is it one of those?

Do you use a primary password for Thunderbird, one that is required when you start Thunderbird?

Like I said before I've used Thunderbird for many years on many different PCs and have never been asked for a password.

I might have used one when I first downloaded it in the early 2000s alongside Firefox.

But if I did, I have no idea now.

Peter

All I can suggest is to post the complete error message and someone using Android Thunderbird may have a suggestion

There's no error message.

I'm being asked for a password I can't remember.

Peter