Organization info on donation

Hi, we want to 'invoice' our donators.
In order to do so we also need to capture the organization name.
In the first part of the donor details, it only has fields for personal information (first name, last name, address, etc.)
In the second part of the donation details there are fields for:
- donation amount
- VAT number

is it possible to have an additional (optional) field: Organization?

Is this something I can change for myself or is this 'hardcoded'?
thanks, Ruud