As a student, you will sometimes be directed to make exact copies of a work, as with copies of historical masterworks. Generally though, you must use your own ideas and imagery or credit the individual(s) whose work you incorporated into your own. Although there are instances where including (nearly) identical imagery by another into your own work is necessary (such as in appropriation artwork or a collage), you must always acknowledge the original creator, both in writing and verbally. For guidance on how much of another's work you may ethically reuse, see the Copyright guide.
Paraphrasing is using another's idea with roughly the same amount of detail but without copying the exact words. Paraphrasing must include a citation, in order to let people know that the idea or the information is not yours. Some strategies for paraphrasing from the MIT Handbook include the following (use multiple bullet points for each paraphrase):
Summarizing is when you incorporate information from another source but on a much broader level. A summary is significantly shorter than the original, only touching on the main points without going into detail. As with paraphrasing, a citation is required. For more information on both paraphrasing and summarizing, see the University of Toronto Handout.
When creating visual and written works, you must give credit to the creator of work that influenced you. In order to properly acknowledge them, you must take careful notes while conducting research. Make sure you record all the bibliographic information (title of the book/artwork, author/artist, date published/created, etc.) for each source you reference.
When you find an interesting fact or mode of expression, make sure to take note of it in writing, along with the source information. When a specific idea interests you, it can help to write your own paraphrase or summary of the information so that when you go back to your notes, you can use the information you recorded without plagiarizing the original (making sure to acknowledge the information's source, however!).
Direct quotations are the exact words of another, enclosed in quotation marks (if a short quote), or indented within the paper (block quotes are required for quotes over four lines long). You should only use quotes that are very important to your work, i.e. a sentence that is crucial to your argument. You should not use quotations for purely factual information such as numbers from a census - this information must be cited, but does not need to be placed within quotes, given its factual nature. For more information, see the University of Toronto Handout.