Just a Quick on how to add a read more link to your posts.
When you want to just show just an excerpt of the post and have a read more button you can do it one of two ways in WordPress.
Now I have showed it via screenshots below.
In the first option in the “Visual tab” just click insert read more where you want the break in the post to be.
So just put your cursor where you want the post to break and it will display the top part but they will have to click “Read More” to read the rest of the post.
Or the second option is where you hit the “Text” option and insert the “more” break again where you want the “Read More” break in the post.
Now I had a problem with the theme that I was using where sometimes the “Read More” was not showing up so I had to go into the setting of the “sparkling Theme by Colorlib”.
Go to: Appearance -> Customize -> Sparkling Options -> Content Options -> Check the show post excerpts.
Now when I checked my setting it was already checked so I just unchecked it and then checked it again then saved, and then it worked.
So if you have a theme that you have an issue with then you will have to search about on the internet as there could be different setting options for different themes.