Paying my mom wage to get Social Security credits

My mother is missing 4 social security credits out of the 40 required to claim social security. Im thinking about paying my mom to be a "housekeeper" with a wage of $8000 so that she can get the 4 credits. What types of paperwork do I and her need to file to make this legal? Im in the state of California, by the way. Thanks for any advice.