[itsme]

The intended way in MSP is creating a song in the library and adding an empty page. The "Title" in the song's meta data is what you requested as "a simple line of text".
That shows a completely empty white page when stepping through the setlist.
This is why I prefer creating "dummy files" for songs that I play from memory. My "dummy files" are usually ChordPro files containing just the song title and the key: {t:Any Song} [C]
When I import such a dummy file as a song, "Title" is automatically taken from the {t: tag. Then I add the meta data I want and categorize into collections (a specific collection for every band I play with) and setlists (a specific setlist per gig).
That's flexible, fast and convenient.