Schools that offer programs that prepare students to directly enter the workforce are know as

Schools that offer programs that prepare students to directly enter the workforce are known as vocational schools

Explanation:

Vocational schools are educational institutions that offer practical postsecondary education and job training in a short period, these system is normally appealing for people who want to be part in the workforce as fast as possible, they are also called trade schools or career schools due to their quick and objective training.

The best name for those schools are "vocational schools" - schools that directly teach a certain skill which is expected to be needed in the future work.

For example, many high schools teach some practical skills, such as programming and engineering and the students can then decide to directly enter the work force, or continue at the university