Paraphrasing and summarizing are very similar. Both involve taking ideas, words or phrases from a source and crafting them into new sentences within your writing.
Summarizing includes condensing the source material into just a few lines.
To paraphrase is to use another author’s ideas expressed in your own words—without quotation marks, since it's no longer a word-for-word quotation. Just changing a few words from the original doesn't count.
Whether paraphrasing or summarizing, credit is always given to the author.