Hi Stanisław,
By default - when you create a report it takes into account who is displaying that report, so with correct configuration one report might be enough for all companies.
Every time new element (document/form) is created in webcon it's assigned to a company (COM_ID, WFD_COMID in database) - there is always a default one (not sure if WEBCON or Headquarters).
Based on that, value which is assigned to all elements, you can define privileges on two levels, which also take into account companies:
* Process
* Workflow/Form
When there are 3 companies defined, then on process/workflow privileges level there will be 4 tabs to manage privileges:
* General
* Company A
* Company B
* Company C
If you specify privileges in 'General' tab it gives access to all instances - so users with 'Access to all elements' will see all elements from all companies.
On the other hand if you will use 'Company A' tab, then specified users will get access to elements with assigned 'Company A'.
'Default for' configuration will handle choosing right company for specific people, but you can also define 'Start new elements' privileges on Process or Workflow/Form level to make sure, that users won't have possibility to start elements for other company.
I'm not sure what do you mean by several forms - have you registered new documents with selected company, or there are multiple form types?
Multiple forms are not required to handle multiple companies - one is enough, but I'm not sure if it's not just a business case which just deals with many form types :)