The minimum wage is the lowest wage set by law that your employer must pay you. Almost every employee must receive minimum wage with very few exceptions in California.
According to The California Department of Industrial Relations, the only exceptions to the minimum wage law are apprentices, children, spouses or parents employed by family, employees of nonprofit organizations and outside salespersons. There is no exception based on the size of a business, but the minimum wage does differ for small businesses. As of 2020, businesses with 25 or fewer employees may pay one dollar less than those with 26 or more employees.
California is unique when it comes to tipped workers. Federal law and most other states allow employers to count tips as part of the wages, which means the employer does not have to pay the minimum wage. So, if you receive tips, your employer cannot count them as part of your wages and must still pay you minimum wage.
Employers also cannot pay you less because you are under a certain age. The law treats all workers equally.
If you work in an area where the local government has also set a minimum wage and that amount is more than the state amount, then your employer must pay you the local wage. The law always sides with you on this point so you get the highest wage possible.
Even if you have an employment agreement, your employer cannot pay you less. You cannot agree to receive lower pay or waive your rights to the minimum wage.