Last modified – last updated date into blog post

Hi guys,
I know that I’m asking about a customization but if it’s possible I would like to know how to add the “last modify date” (last updated) in a single blog post.
I have found some guide on the web but they suggest to add a code into a single.php file that I don’t find in Minicorp theme. Others suggest to modify the function.php file but the last modified date appear in all the parts of the website also in the home page but I want it just in my blog posts.
Here a complete source: https://www.wpbeginner.com/wp-tutorials/display-the-last-updated-date-of-your-posts-in-wordpress/

Do you know if there is the possibility to do that? Lot of SEO Specialists say that it is a good way to says to Google that an article is updated and it can takes benefits; I would like to test it.

Thank you for the support.
Bye! :)