If Someone has been arrested they are taken to city or county jail for booking/processing. When this process is complete then bail is set and determined for each individual circumstance.
Posting a bail bond is a financial guarantee with the court system that the defendant/accused will be in court for each instance that the court needs him or her.
Expect to be charged a premium or service fee (most often this is 10% of the bail amount) which is set by the California licensed Surety Companies and California Department of Insurance. Once the premium is paid the money will be placed on the bond and the defendant will be released from jail upon the promise that they will return when the courts at a specific time, place and date.
Make sure that you are confident in the fact that the defendant will be available and in court every time that the court requires them to be there until the bail is exonerated. You will be responsible for their fulfillment of this promise and if not fulfilled you will be responsible for the full amount of the bond and other possible expenses incurred.