The defendant can post their own bail or ask a family member or friend to post it. If the defendant uses a bond company, the company may require the defendant to have a co-signer (someone who will help the company find the defendant should they fail to appear).
Bail information is considered public record in the State of California, meaning that anyone (not only defendants themselves) can request this info. The details can be accessed via the Public Access to Court Electronic Records (PACER) system or the Criminal Intake Section.
For example, in California, bail bond records are generally public and accessible via the Public Access to Court Electronic Records (PACER) system.
When you work with a bail bondsman, you can remain anonymous if you wish. The only people who will know your name are the bail agent and the court. Your name will not appear on any public records associated with the case.