Hi Lynn,
Thanks for reaching out to us.
Yes, you can add a logo by first uploading it to the Photo Basket (at the bottom of the editor) and then dragging it onto your main image. You can then also optionally use the Advanced Blend Modes drop-down on the Photo Properties dialog which appears to make the logo blend with your image (try the different options within this drop-down to find what looks best).
Let us know if you have any further questions!