Every model needs a portfolio and composite cards.
These are the basic marketing tools of the model, just like a resume would be to any other job seeker. If you are already with a reputable agency, they will likely have a list of competent photographers who you can choose from. Also, other models might be able to give you suggestions on the photographers that they have preferred to work with. Unless you are posing for the photographer's work in exchange for free portfolio prints, you'll also have to consider a budget. Before having photos done, it's best to talk with your agency to find out what their suggestions are.