Using Same Email for multiple users

Hi, I have multiple users in the company and each of them is using his own personal email, but all have to use an additional common email for the sales inbox, and that's through where we get in contact with the clients, but when i set up multiple users with that email, it's seems to be different, the whole point of it is that if one is working on a certain email, they would drag it to their folder so that others don't see it and there is no duplication, but it seems to be the opposit, even when one of them drags an email to their folder, the others don't see the changes, and they don't even have the same folders.

Is there any way of fixing that or working around it ?