If you are looking for a new job then you may wonder about registering with a recruitment agency. There are different types of recruitment agencies and all charging fees in different ways. If you are looking for a permanent job where the recruitment agency finds the positions for you but then you are employed by the company directly, they will not normally charge you a fee, instead their fee is charged to the company who employs you.
If you are wanting to work for a temping agency that will find you work quickly but you may be working at a different place every few days then they will probably take a cut from your salary.
Recruitment agencies will usually add your CV to their database and then search relevant jobs to find a suitable match. They will then either send you the details of the job or ask you if you are interested in applying for the position or they will forward your CV on to the company advertising the vacancy to see if they wish to invite you for an interview.