Creative Commons licenses are a way in which people can share their work, and let it be used by others under specific conditions, without giving up their copyright in their work. The six main CC licenses all require attribution for their use in any manner. However, while the license requires attribution- acknowledgement of the creator of a work, it in no way implies that the original creator endorses the user’s presentation of their work, and this is explicitly stated in the license.
All Creative Commons licenses are not created equal. They all require attribution- the acknowledgement of who originally created the material, but there are six main types, divided into two broad areas. The first allows anyone to use the material, including use for commercial purposes. The other group is for use in non-commercial form. Within each group there are further divisions, for whether the material can be shared, and whether derivative works can be made from the original. There are also two additional licenses. One is the Creative Commons license in which the creator gives up all right to the work. The other is a Creative Commons public domain license, with which a work is certified as being in the public domain, to the best of the certifier's knowledge.
As well as using material with a Creative Commons license, you may decide to let others use material you created. When an individual uses a Creative Commons license on their intellectual property, it means that they are allowing others to use their work, in certain specific ways, depending on the chosen license. As a creator, whether you are willing to let your work be used solely in a non-commercial way, without any permission to modify or share the material, or you are willing to let anyone use your work in any form, as long as they attribute it to you, the original creator, you need to select the right license to accomplish that.
Image: Creative Commons license matrix- CC site