Hi, you could script it using the API calls to automate the process of adding the account and then adding it to the mailing list.

To add a user to a domain

To add subscribers to a mailing list:

Yes, thank you for your suggestion.

But for a company that don't have IT/API dev, they will get trouble.

The problem with adding, say, a slider control for Mailing Lists when adding/editing a User is that it can get terribly unwieldy for domains that have hundreds of lists. We have something similar in SmarterTrack for adding permissions to KBs and KB folders and, to be honest, when you have a large number of KB folders, and those folders have sub-folders, it gets a bit difficult to use.

Using the API is really the best way of automating this as you can automate the entire user process, including adding them as subscribers to one or more mailing lists. So Sebastien's reply is the way to do it. 

Thanks.

Can we use something like this forum's tag. So search "listing name" and it will suggest for selection.

And it will be easy to use when "hundreds of lists".

I agree with the API usage. That’s what it’s for 👍👍👍