In most cases, you may not copy text from other sources into Wikipedia. Doing so is a copyright violation. Always write the articles in your own words and cite the sources of the article. Copyright violations are often speedily deleted. Facts cannot be copyrighted. Titles of people or publications cannot be copyrighted. Text and illustrations prepared by the U.S. government are not copyrighted; they are in the public domain and can be used without permission, but to avoid plagiarism a citation is required indicating their source. Material from US states and local governments is copyrighted, as is material from foreign governments. Copyrights expire after many years and then the text becomes free.

As a general rule, do not copy text from other sources. Doing so usually constitutes both a copyright violation and plagiarism (exceptions are discussed below). This general rule includes copying material from websites of charity or non-profit organizations, educational, scholarly and news publications, and all sources without a copyright notice. If a work does not have a copyright notice, assume it to be under copyright-protection.^[1]

Generally no, unless the source is already under a license compatible with Wikipedia (such as CC BY-SA), or you donate the source under a free license. A free license makes the source available for anyone – not just Wikipedia, but anyone using Wikipedia – to use, edit, and copy it for any purpose, even commercial ones. It's unfortunately common for new or inexperienced editors to become frustrated when content they have copied from websites they own (or work for) is removed or articles tagged for speedy deletion. Unless the content is verifiably compatibly licensed or public domain, however, Wikipedia can't retain it. Even if it is compatible, the content must comply with other content policies for us to be able to use it. Often, the tone and structure of the source itself might not be appropriate for an encyclopedia article, and most content on Wikipedia should be based on secondary, rather than primary, sources.

If you have published content on another user-generated website, they may have required you to grant them exclusive license, in which case you cannot contribute it here. Sometimes even when sites do not require exclusive license, such as IMDb, it may not be possible for you to use the content here as it may not be possible to verify that you are the individual who placed it there.

No. Superficial change of copyright-protected text is not enough. Wikipedia articles must be written in the author's own words. If the way in which a source has said something is important, please employ quotation.

No. While your user page and talk page may include brief quotations from copyrighted text, Wikipedia cannot host extensive copying of non-compatible copyrighted material anywhere, not even in talk or user pages, not even temporarily.

Brief quotations of copyrighted text may be used to illustrate a point, establish context, or attribute a point of view or idea. Use of copyrighted text must be in compliance with Wikipedia:Non-free content criteria policy. This means that the quotation must not be replaceable with free text (including one that the editor writes), must be minimal, must have contextual significance and must have previously been published.

Yes, you can copy parts of one Wikipedia article into another, but you must link to the source article in your edit summary. Original content contributed by users can be freely used if the original author is properly attributed. If you have copied text but forgotten to use the edit summary, this can be easily corrected: You can make a dummy edit by making an inconsequential change to the article—such as adding a blank line to the end of the article—and link to the source article in edit summary then. A note such as "content copied from [[source article]] on 1 January 2012" works fine.

It is also recommended to make a note on the talk page of the source article that copying has occurred, because the source article cannot be deleted as long as content from it is used. The template {{copied}} can be used for this as well as on the destination article's talk page.

It is acceptable to copy text from public domain sources or those that are explicitly licensed under a compatible licensing scheme. However, if you decide to do so, a dedicated attribution template must be used, and it's simply not enough to only mention the references and use inline citations. Attribution gives credit to the original author and is always required whether or not the text is free: see Wikipedia:Plagiarism. There is a guide for embedding freely licensed content (either public domain or Wikipedia Compatible licenses), at Wikipedia:Adding open license text to Wikipedia and the Copyright FAQ.

In case of uncertainty, please ask at Wikipedia talk:Copyright problems or Wikipedia:Help desk for input from other editors.

If possible, screenshot the interface instead of copying the text. Screenshots fall other "non-text media" in Section 7d, which allows the use of some free copyleft licenses incompatible with CC-BY-SA. For instance, on Wikimedia Commons, the use of GNU GPL-licensed media is allowed. For help with adding screenshots to Wikipedia, see Help:Images.

• Do not copy the interface text of GPL (or other copyleft licensed) programs directly onto Wikipedia.
• Do not copy the interface text of Apache-licensed (or other patent retaliation licensed) programs directly onto Wikipedia.

While copying text from the interfaces of attribution-only licensed programs, like those licensed MIT or BSD, seem compatible with CC-BY-SA, the Creative Commons has not declared compatibility. This, and the fact that some ostensibly attribution-only programs come with additional terms like the Commons Clause, mean you should screenshot the interface.

• Do not copy the interface text of attribution-only programs directly onto Wikipedia.

Yes, you can copy interface text from public domain programs, or CC0 programs, directly onto Wikipedia, as public domain programs are compatible with the CC-BY-SA license used by Wikipedia.

• Make sure the program is explicitly licensed CC0 or public domain, and use {{CC-notice}} or {{PD-notice}} to indicate this.