This is a simple stationary design based on nature, using an illustrated leaf. It uses a green palette, but is fully customizable for other color choices. This is an example of what one could do for different stationary items. This would easily let your customer know who sent the items.
I have been working on a few different design elements lately, and this one came as I was working on a roll-up banner, which was also based on the different elements. I did a few sketches to figure this out. Once, I got a design that I was happy with, then I created the final product using Illustrator