Apple iPhone and iPad access to Thunderbird

Recently had an internet interruption for most of the day. When service was established email on my PC works normally, but now am unable to access email from my iPhone or iPad. Each attempt was met with the same message the “incorrect password”. I know the password entered was correct for access to the mailbox on the server. In researching this problem I found that many email providers now are using an App Specific Password when accessing mailboxes and this would require a unique password generated by the email provider’s account administration page. How do I access this page and create the necessary password to access my mailbox.