The text composition window size is fixed.
Sometimes it's helpful to display both the clip and sequence preview screens. Click OPTIONS | DISPLAY and check the box.
Text is composed within the boundaries of video in the sequence preview window (not in the text composition box).
If a line is too long, press <enter> to split the text into multiple lines.
Use these controls to position it...
Or simply drag the text in the preview window.
To change size and colors first select the text, then apply the changes.

This on-line tool can be useful... HTTPS://GILLMEISTER-SOFTWARE.COM/online-tools/text/add-line-breaks_change-line-length.aspx
Using the tool, compose text in its top window, then set the line length to what will fit best in Videopad preview.
Click the bottom section to see the result, and press the COPY TO CLIPBOARD button.
Now paste the text into VP's text editor, using <ctrl-V>. Very slick.