As noted in the Stack Exchange Terms of Service and in the footer of every page, all publicly accessible user contributions are licensed under Creative Commons Attribution-ShareAlike license as follows:

• Content contributed before 2011-04-08 (UTC) is distributed under the terms of CC BY-SA 2.5.
• Content contributed from 2011-04-08 up to but not including 2018-05-02 (UTC) is distributed under the terms of CC BY-SA 3.0.
• Content contributed on or after 2018-05-02 (UTC) is distributed under the terms of CC BY-SA 4.0.

The license applicable for each Question and Answer revision is available on the post timeline. See this post for more information.

Please read the terms of service and the full legal text of the license carefully for more details on how your content can be used and for how you can use publicly accessible content contributed to the site by other users.