PDFs
A PDF uses the built-in reader. You can scroll it, and you can select text to highlight a passage. See Highlights.Images
An image opens large enough to read. You can zoom in. Type controls (Aa) are hidden for images, because there is no text column to restyle.Text, Markdown, and Word
Text files, Markdown, and Word documents open as reading text in the column. You can set the type and use Focus, the same way you do for an article.Accepted file types and the 20 MB limit are listed in Save a file.