Yes to be able to bail someone out of jail on your own you must be 18 years old or older and show your drivers license or ID.
For some bail bondsman companies they may even require you to be at least 21 years old before they'll allow you to sign an agreement with them to post bond for someone to get out of jail.
But if you're paying cash money for the bond all you need is your drivers license or ID and the cash money in full to bond the person out of jail.
You can also use debit or credit cards in most jails to bond the person out of jail and if the person shows up to all court dates the money for the bond is returned.
But if not the courts keep the money you used to post bail.