How to implement a mini idea for a small office?

Question

CRM

Hello!
I ask for help with choosing a free CRM or suggest an alternative (it is important that the client is an OC Windows server)
There are 4 laptops on which you need to install a client and a PC (OC Windows) on which there will be a server.
Tasks: adding, editing customer contacts, editing documents. (such as Excel, etc.), etc.
Plus, you need client authorization on the server and flexible server configuration. (possibly udalenka)
Answers further on the development of the topic!

Answer 1

Take Bitrix24. For 10 people free of charge.
The OS doesn't matter.
The cloud is better than your own server.
If your server is important, then you can do this casepress.org/skaz-o-tom-kak-my-dvizhok-dlya-blogo...