Members who have recently found your profile are not so likely to enter a paid session immediately and appreciate being able to enter Free Mode first so they can familiarize themselves with you and your services. By offering this mode, you can increase the number of people in your room and the potential of paid-for modes; be careful not to give away too much for free, or there may be no incentive to pay.
Offering Free Mode can also list you higher on the webcam pages. See the related article for more information.
You can manage how long members can be in Free Mode (with you) here.
The DirectCam modes can be changed from the Settings area, while in the broadcasting area, as well as from the full settings page located here: https://m.adultwork.com/account/directcam/management?activeId=8.