1. On a website, select some text and right click.
2. Then left click on 'Copy link to highlight'
3. Now the link has been saved to the clipboard, you just need to past it.

For example, here is an original link: 
https://www.codegrepper.com/search.php?q=copy%20link%20to%20highlight

And this is a highlight link for the same website:
https://www.codegrepper.com/search.php?q=copy%20link%20to%20highlight#:~:text=On%20a%20website%2C-,select%20some%20text,-and%20right%20click