What is Creative Commons?
Creative Commons provides free, easy-to-use copyright licenses to make a simple and standardized way to give the public permission to share and use your creative work–on conditions of your choice. Instructors and students can freely use Creative Commons licenced material and can apply Creative Commons licences by using the licence tool to material they create. This allows sharing of resources with other educators, schools, and the Open Education Resource (OER) community at large.
The Anatomy of CC licenses

Every Creative Commons license has three layers: the lawyer-readable legal code, the human-readable deed, and the machine-readable code. As the only legally-operative layer, the legal code is the primary layer of the CC licenses.
License Types
There are six Creative Common licenses (plus “Public Domain”) that you can choose to assign to your creations. The License types are composed of the following four conditions:
All CC licenses require that others who use your work in any way must give you credit the way you request, but not in a way that suggests you endorse them or their use. If they want to use your work without giving you credit or for endorsement purposes, they must get your permission first.
You let others copy, distribute, display, perform, and modify your work, as long as they distribute any modified work on the same terms. If they want to distribute modified works under other terms, they must get your permission first.
You let others copy, distribute, display, perform, and (unless you have chosen NoDerivatives) modify and use your work for any purpose other than commercially unless they get your permission first.
You let others copy, distribute, display and perform only original copies of your work. If they want to modify your work, they must get your permission first.
Choose a License
You can easily add a CC license notice to your website by visiting the CC license chooser. At the chooser, simply answer a few questions, fill in the fields you need, and receive an already formatted HTML code or descriptive text to add to your offline documents.
Suggestions
If you are dealing with content that does not natively exist online (i.e. any file created and saved on your computer), adding a license graphic/descriptive text generated on the CC license chooser will make the license of your choice explicit for Lawyer and Human, but not Machine. Adding the Machine-Readable layer to your content is important as it is the way people will discover your content. The machine-readable layer is often added when you upload your content online. If you are publishing your content on your own website/blog, you can simply get the HTML code on the CC license chooser, and embed it on the footer area of the web-page, which will make your CC licensed content Machine-Readable. Otherwise, here are some platforms that will give you an option to add Machine-Readable layer to your content:
Flickr will allow you to upload up to 1 TB of image or video files online. Click here to get the list of file types supported.
Wikimedia Commons is an online repository of free-use images, sound, and other media files. As of December 2016, there are many commonly used formats that are still not supported on this platform (i.e. mp3, wma, mpeg, mp4, etc.), but there are many alternative file types they support that you can convert your files into.
PDF documents
As of December 2016, there is no platform like Flickr for uploading PDF documents with easy licensing tag, but PDF provides two mechanisms for the storing of metadata, such as license information, in the file. See this page for more information on adding a metadata to your PDF document. There’s also an open-source application (available only on Windows) called CC PDF Converter that lets you add CC license of your choice to your PDF document.