Silhouette America does not currently offer any stencil fonts or automated methods of creating a stencil.
The easiest way to achieve a stencil effect for lettering would be to obtain a font style that is designed in such a format already and use the Text tools to just type out the desired lettering.
However, a work-around can also be used to manually connect inner parts of images to the outside in order to create a bridge for stencil creations.
The following steps can be taken to manually create a stenciled letter:
This will yield the following result: