|This is an information page that describes communal consensus on some aspect of Wikipedia norms and practices. While it is not a policy or guideline itself, it is intended to supplement or clarify other Wikipedia practices and policies. Please defer to the relevant policy or guideline in case of inconsistency between that page and this one.|
|This page in a nutshell: With the exception of short quotations, text from other sources may not be copied and pasted into Wikipedia. Doing so is a copyright violation and may constitute plagiarism.|
In 99.9% of cases, you may not copy and paste text from other sources into Wikipedia. Doing so is a copyright violation and may constitute plagiarism. Always write the articles in your own words and cite the sources of the article. Copyright violations are often speedily deleted.
Can I copy and paste text to Wikipedia that I got from somewhere else? 
As a general rule, do not copy and paste text from other sources. This includes websites of the charity or non-profit organizations, educational sources and all sources without a copyright notice. If a work does not have a copyright notice, assume it to be under copyright-protection.
Even the employees or representatives of an organization may not copy and paste copyright-protected text from the organization's resources into Wikipedia. However, license owners may donate their texts to Wikipedia, as described in Wikipedia:Donating copyrighted materials.
But surely I can copy from this? 
It is acceptable to copy and paste text from public domain sources or those that are explicitly licensed under a compatible licensing scheme. (In case of the latter, attribution of the original author may be required.) However, copying and pasting contents from all other sources entails what is explained above.
In case of uncertainty, please consult Wikipedia:Copyright problems.
Can I copy and paste if I change the text a little bit? 
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.
Can I copy and paste text into a user page in order to work on it? 
No. Wikipedia cannot host copyrighted material anywhere, not even in user pages, not even temporarily.
What about quotes? 
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.
How about copying and pasting from one Wikipedia article to another? 
Edit summary (Briefly describe the changes you have made)
☐ This is a ☑ Watch this page
You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
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.
- Most websites (and other sources) are automatically protected by copyright under rules such as the Berne Convention, even if the author did not apply for copyright or place a copyright notice in their work.