After you’ve set your identity and obtained your driver’s license item, walk to the first office to your right and enter the orange marker near the desk to get your job from the hiring center.
Here is where you will choose your job. Simply select which job you’d like to do and hit [ENTER] (A on the Controller).
There are also job points near the garages for various jobs, for your convenience in changing jobs based on your current character. To check to make sure You’ve successfully selected a job, look in the upper right corner of the screen for your career title.
Congratulations! You are now a legal, employed citizen of San Andreas.
For specific job information and how to switch careers, see the jobs section of the guide.