Paraphrases are for putting short texts into your own words. You will try to keep all the details. for example:
Original text: "I am still learning" (Michelangelo, at age 87)
Possible paraphrase: "When Michelangelo was 87, he still felt he was learning new things."
Summaries are for longer texts. You don't give all the details because it would be too long. For example, Harry Potter and the Philosopher's Stone is a whole book, but it could be summarised in a few words, like this:
"Harry Potter, an apparently normal 11 year old boy, was invited to attend a school of witchcraft and wizardry. He made good friends but also some enemies during his first year at the school. With the help of his friends, he struggled to defeat a dark wizard who had killed Harry's parents when he was just a baby."
There are some very good reasons for using paraphrases and summaries, rather than quotes:
Here are two texts taken from a student's essay. Have a look at them and answer the 4 questions below.
A. The Royal Society (1999) eventually admitted that Marshall's results strongly indicated that ulcers were an infectious disease rather than a malfunction of the stomach.
B. The Royal Society said (1999), "These results were a major challenge to the prevailing view that gastric disorders had a physiological basis, rather than being infectious diseases."