This looks like a pillowcase dress that you would make for a little girl. I bet it is a similar pattern and can be easily adjusted to fit an adult. :)
Hankie Pillowcase Shirt Download PDF sewing pattern PDF download from Indygo Junction
Pillowcase Dress Tutorial for Adults and Kids! - girl. Inspired. - maybe use ribbon or bias tape for wider straps. Or could be a cute nightdress.
Upcycle vintage pillowcases into unique eco shopping bags! Very easy sewing project you can complete in 20 minutes.
The Crafty World of LotusBomb: "Pillowcase" Top Tutorial
Great DIY sewing tutorial I've already made a few of these envelop pillow cases! Easy to customize for any home decor.
Pillowcase shirt tutorial, how to make a pillowcase shirt
Pillowcase Tank Top ...i have been looking for this for awhile...so cute and seems easy to make
Perfect Pillowcase Shirt | FaveCrafts.com