You have a lot of freedom with the cards you made. The below images are examples. Please don’t take them as something you need to copy.
You can buy blank cards at a stationary store, local arts and crafts shop, or other retailer and design the front with whatever materials you have available – markers, gel pens, colored pencils, collage materials, etc..
If you don’t want to buy cards, you can cut a piece of cardstock or other heavy weight paper into thirds, like the one on the left. That one fits into a regular letter size envelope. The design on the front was made with paper cut-outs.
When you write a message inside, keep it positive and inspirational. If there’s a specific need of a recipient, that will be included in the request so you can make it more personal.
It’s a good idea to test your mark-making tools before completing a picture. Colored pencils and gel pens work great. The below cards were done with collage and watercolor. I would not use acrylic markers or paint unless your paper is specifically created for mixed media.