Use Apple's or Yahoo/Comcast's app password generator ?

Use the Yahoo generator.

I’d evaluate whether I wanted to go through this migration again should (when?) Yahoo change directions, and whether I wanted to move to Apple iCloud Mail, or to some other email provider, or a personal domain hosted at Apple or somewhere.

Suzy2014 wrote:

Thanks, @Mr.Hoffman. Did you go through this migration and are you using Apple mail successfully after it?

I have hundreds of websites that use the Comcast email address as my user ID that I would have to change + I would have to update email addresses in many other accounts, documents, etc. This is why I hope to be able to get through this migration. Unfortunately, companies/providers change direction and one is at their mercy. None guarantees that they will not change, stop their services.

I’ve gone through multiple previous ISP mail and third-party mail provider migrations, and some years ago have moved to my own registered domains.

Registering a domain means I have to deal with the hosting whether at Apple or elsewhere, but it also means I keep the email addresses for as long as I pay the domain registrations and hosting.

As for one hosting option here, Apple domain hosting for private users is included with an iCloud+ subscription.

I moved to domains before I had hundreds of websites, though.

And yeah, whatever you pick here is going to be a hassle. Yahoo is probably the easiest here for this specific migration, but that also depends entirely on how long the domain forwarding from Comcast to Yahoo continues, and on whatever plans Yahoo makes.