It is important that your document be formatted in the same way from beginning to end. If you find anything that looks wrong, you can format it as plain text.
If you use selective pasting and unformatted text when pasting other people's paragraphs, you will become your own article after editing the format uniformly.
But people check whether you have copied other people's articles, and you can copy a certain paragraph (or a certain line) to search. If you don't write it yourself, it's easy to find the original source.