I have about 20 000 subscribers. I want to select them all, and add them to a list "all".
I see that I can select only 200 at once, so I was wondering whether there was another way.
If you have Starter or Essential version, then I am afraid this is not possible
If you have Enterprise version, then you could use Mass actions to subscribe all subscribers to some other list
Yes, I have an Enterprise version. OK great. I found it Automation > New mass actions.