To create open access materials you will need to apply an open license.
Creative Commons helps you legally share your knowledge and creativity to build a more equitable, accessible, and innovative world.
Creative Commons Licensing (Wakelet)
This is an annotated list of resources on Creative Commons Licensing explaining the nature and usage of this type of licensing.
GNU Free Documentation License
Published software should be free software. To make it free software, you need to release it under a free software license.