When buying a property in Portugal, and before you start the research, it is important to understand that owning a property in Portugal can be done in two ways:
Private ownership, with the property registered to your own personal name(s).
The most common way to own a property is to register the property to your own name(s). Your lawyer will do a background check on the property to make sure the villa, pool, etc, are all correctly registered.
Corporate/company ownership, with the company shares registered to your own personal name or holding company.
The company ownership solutions might, or might not be suitable to some buyers, but it is important to research this before you start the property hunting process. Many of the higher budget villas are owned by a company structure whereby the company owns the property, and via a share transfer, the ownership can change hands. The mostly practised forms of company ownership for properties in Portugal are with a Portuguese LDA (limited company), a UK LTD, or an offshore company in Malta and Delaware (on the white list).
With a company/share sale or purchase besides a legal check on the property, due diligence will take place on the company.