The person will have to become an Etsy member in order to purchase from you on Etsy.
Setting up a reserve listing is easy. Just put "Reserved for (the person)" in your title. I also begin my listing description with "For (the person) only, please."
Then I write a full description and include photos. I do this because my reserve listings always get views from others besides the intended buyer. This way they can see what I have to offer and may choose to purchase another item from me. People are curious, and click on reserve listings!
Lastly, I include the buyer's name as one of my tags and send a link to the item so he or she can be sure to find the reserve listing in my shop.