Different colleges may have different deadlines for applying for admission. You should check with the college you are interested in and see what they recommend. Usually, you should try to apply in the fall of your senior year in high school or about a year before you hope to attend the program. Some colleges do not allow full-time students to work. Sometimes students can get campus jobs.
Some colleges have night classes for people who work during the day.
You will have to ask the college you are interested in about working and studying at the same time. There are many kinds of degrees. Your choice of program will depend in part on the degree you want. The degree you need depends on your career goals, your personal goals, and your ability to complete the program. You should explore your career interests and abilities before selecting a major.