Automatic recurring plans with off-line payment

Is there any module to manage it for my customers at frontend?

There's no functionality to pay offline baskets from frontend. The user, or you as an admin, needs to visit the users Subscription tab on their profile. Then go through the normal process of selecting a plan or using the renew button for an existing plan. Once on the basket use the offline payment gateway button then click the confirmation link on the subsequent page. You, as an admin, can now pay that basket from backend in CBSubs > Baskets.

Thank you for the instruction. What I didn't understand: what is the way to get the subscription tab from the user as an admin? I need a possibility to see at the frontend all my users with a subscription and the possibility to manage their profile. But I cannot see this way.
The other way is to login in with the login details from my users. But I don't know the passwords, so I have to change it. This is not a good way, I think.

You do not need those users login details. You just need to login with an administrator account and navigate to that users profile. You can then use their Subscription tab on their behalf. You need to be sure the plans you're wanting to subscribe them to are actually access to them (and you) for this to work though.