Some programs are more selective than others, but many admissions officers are looking for similar qualities in applicants. Each school will need to see proof of a bachelor's degree, but the degree doesn't necessarily have to be in social work. Applicants who do have a BSW can apply for a school's advanced-standing program if it offers one, which allows students to complete their MSW coursework faster. Many schools either require or prefer that their master's students earned a minimum GPA of 3.0 as undergraduates; advanced-standing applicants will need to prove a certain GPA in their previous social work courses.
Most programs require applicants to submit letters of recommendation and at least one personal essay or statement of intent. Social work departments want to admit students who think critically about social problems and how to solve them, and these documents can go a long way toward proving a student's commitment to the discipline. Prior jobs in social work can provide real-world examples of this commitment that applicants can draw from — although work experience usually isn't required for acceptance, about 79% of MSW graduates had some professional experience before their graduate studies.