Learn how to add suggestions in a PR review. In the files changed view on GitHub, select the line you want to make a suggestion like you would a regular comment. Right above the text box, simply click the first button that says Insert a suggestion
. On the main page, it shows the suggested change and even has a way for the author to merge the change.
This is a way to give specific feedback that allows the author to commit your changes with the click of a button from the browser.