Although the fonts prefixed with “MGM” are designed for traditional three-letter monograms, you are by no means restricted to three letters. For example, if you just want the large center letter, enter a space and the character you want.
Type a space before a letter for a large single letter
For fun, you can use a monogram font with entire words. This method works best with all capital letters and fairly short words.
Sample above uses MGM Rounded applied to a word.
Overlapping letters are sometimes needed for your design, and when you do that within a lettering object, the stitches that are hidden get removed automatically: