The Gutenberg editor

1. When you have typed the text into a block, you select the word you want to link to a pop-up text. Then you click on the 3 dots and choose "Edit as HTML"

2. Here is the code you need to create the pop-up text.

<a title="This text will display on your website when you hover over a character or word" href=" ">[3]</a>

3. Change the line "This text will display on your website when you hover over a character or word" into your own words you want to display. And replace the [3] in anyword or character you like.

4. When you have entered the code, you can go back to visually.

5. After that, click on preview to see if it all works correctly, if so you can updat/publish the page.

6. The [3] is linked now to a pop up text

7. Website result when people hover the [3]