Modeling agencies are those companies that will sign hundreds of models and make sure that each of them will get a job in the modeling world. If you are planning to sign a contract with one of these agencies, you should understand exactly how they work and make sure that everything is clear before they hire you.
Most model agencies already have contracts with various companies that are searching for models. Whenever one of those companies needs a few models, they wont post an ad in the local newspaper, they will contact the model agency and ask for what they need. The agency will take a look at the requirements and choose a few people from the portfolio. This is why models need to be represented by a talent agency. If the one you choose is working with dozens of contractors, the chances of being picked are quite high.
The agent will take care of any monetary issues that might appear, including the initial negotiation with the contractor. You will receive an offer and 10, 20 or even 30% of the entire amount will be taken by the modeling agency. They will also take care of the transport costs and any other issues that might arise. In essence, you will simply have to answer your phone and accept or decline the offers. Super models are usually hired with an exclusive contract, but chances are that you will start with a non exclusive contract. In this case, you can sign with more than one agency and you have higher chances of getting modeling jobs.
Modeling agencies are still around because they are good at what their do. It is in their interest to help you earn money by finding the right modeling gigs. The more money you make, the more they earn, so you can be sure that agents will treat you nicely.
Each modeling agency can find various jobs in the modeling world, so you can expect anything from walking on the catwalk to taking some photos for a magazine. If you want to do hand modeling or something similar, you should figure out if the talent agency you are interested in could offer those types of jobs.
Joining a talent agency costs close to nothing. You will need to send in some photos and a few other things for your portfolio. After that, you just have to wait for the call and start modeling.