Long and short answer...... Go to City Hall and look up names via Assessor's Office. Ask your Realtor to help you (because he/she can get the names from a Title Company, MLS via Tax Data or Realdex/Metroscan to which most of us subscribe.)
Owner information is made public through the county's Assessor-Recorder office (in San Francisco, our county and city are the same) but it is not easy to find this information online and the records are not always current. The property tax statements can be pulled up by address, but they do not show names online and the deed can be ordered if you know the personâ€™s name, but it does not show the address online so you would really have to go to City Hall and look through the physical records for the current (buyer) and previous (seller) names.
The MLS has a place for the owner (sellerâ€™s) name but it is usually left blank.
The best thing is to go through your real estate professional, who will have access to online title company systems showing the chain of title (current and previous owners).
The Azari Group
Do you need help with something like this? To locate buyer/seller data for one transaction is fairly simple and straight forward. To do so for a large number of transactions would take time and resources.
I hope this answers your question. The names of parties to a transaction are available online - for a fee. But most Realtors could probably dig this up on a case-by-case basis.
The City & County hasn't moved into the 20th century yet and probably won't till we can get enough taxes in the kitty to pay for the access.
There is a "work in progress" at the CCSF Index of Records site but . . .