Which Stack for SMB Steel trading company

First of all. I am fairly new to web programming.
We have a small company for trading steel products and working as a middleman for steel factories and steel workshops for construction. We have 15-20 employees.
Still now we are using physical books for accounting and only an excel sheet for inventory and pricing. What I want to do is create a system for our company that would be:
initially>
-Easy to take inventory.
-Give product oversight
-Tech illiteracy friendly
-create receipts
eventually>
-sell products online
-build CRM
-marketing and email newsletters
-Social media outreach
now my question is can I do it cloud based? if so which stack to use?
or if I should go in house server based solution as we want the maintenance cost to be as minimum as possible.