Original:  Trainee programs and graduate programs are arranged by private companies and public sector employers where the trainee is offered the possibility to take part 6 to 20 months training programs . During the duration of these programs, the trainee is expected to receive a salary as well as is expected to have full-time employment awaiting in the company when the program is over.
Revised:  Trainee programs and graduate programs are arranged by private companies and public sector employers where the trainee position has a varied duration depending on the company's program . During the duration of these programs, the trainee is expected to receive a salary as well as is expected to have full-time employment awaiting in the company when the program is over.
Edit intent: clarity