I have already ready WEBsite with user authentication.
I need to implement corporate accounts functional, so that users of this account can go to the link corporate_account_name.main_domain.com and saw the same site as in main_domain.com only this version especially for them.
How to do it and where to dig? (or at least a list of technologies, frameworks):
There is django-tenant-schemas package, which seems totally fit your needs.
A brief description of how it works (from docs):
Tenants are identified via their host name (i.e tenant.domain.com). This information is stored on a table on the public schema. Whenever a request is made, the host name is used to match a tenant in the database. If there’s a match, the search path is updated to use this tenant’s schema. So from now on all queries will take place at the tenant’s schema. For example, suppose you have a tenant customer at customer.example.com. Any request incoming at customer.example.com will automatically use customer‘s schema and make the tenant available at the request. If no tenant is found, a 404 error is raised. This also means you should have a tenant for your main domain, typically using the public schema.