The HTML block in Moodle is one of my favorite and one of the most underused features of Moodle. This block allows you to add any HTML you’d like in a block on your site. You can have multiple blocks with different content. For example you could share links to library resources, such as Lib Guides, or use it to post office hours or TA contact information.
As an example here is a screen shot of an HTML block with information on office hours and a link to my Zoom personal Meeting room, library links and a link to a textbook for the course.
(It is usually at the bottom right of the screen but may vary if you have a different theme active. )
When you choose HTML block you will get a blank block you can configure. Click the sprocket icon to edit the block. On the next screen you will see the standard editor where you can add your text, links and images. You can click the 4 pointed arrow to move the block to another location on your site.