Hi there,
I am a SharePoint expert with over 7 years of experience on application development and configuration.
With current requirements, We only need to do following:
1. Create document libraries for your companies
2. Grant permission for your users on each document libraries
3. Develop a SharePoint time job to send out email notification automatically.
For additional requirements (customization), I need to have more details, so I can give you an estimate.
My rate is 15$/hour
I am looking forward to receiving your reply soon.
Have a great day!
Thanks,
Hai