I just redid my site using Twenty Twenty and it looks 'okay' but at the top of every page there is like a 24pt block that says "Add Title" in Bold. It creates a lot of white space between where the Site Identity logo/tagline is at the top (and the Menu); and where content begins below it.

I've scoured the posts and come up with several reoccurring suggestions for adding CSS code under Themes/Customizing/Additional CSS. Here is what I found in other questions:

.entry .entry-header { overflow: hidden; display: none; }

.site-header { padding-bottom: 0; }

.entry-content, { margin-top: 0; }

..None of these works to remove the white space, or the 'Add Title' on every page when I open and existing page or add a new one.

Again, using Twenty Twenty theme, just updated to ver 1.3 with the 5.4x security update (as of 5/18/20).