If you are looking to make text look "flat" against a surface in a design app:
: Use the Annotation Tool by clicking the annotation icon in the text toolbar. Navigate between notes using the right arrow key or "Enter" to continue typing across the score.
: To make text look like it's laying flat, users often Skew or Angle Text using the distort tools.
To create or add text using (the music notation software) or related design tools, follow the specific steps for your platform: Flat (Music Notation Software)