These cute envelope cases could be made in any size. I show a lined version at the end of the video tutorial below. Lining a case is really easy to do, don't let it scare you.
Simply sew the fabrics RST (right sides together) around the perimeter leaving an opening of 4-5" at the bottom.
Turn RSO (right side out).
Press opening inwards and sew closed.
Always press vinyl from the fabric backing or the lining side - NEVER use a hot iron directly on the vinyl itself.
The PDF download for the pattern is for sale here.
Be sure to print at 100% or "no scaling".
If you're new to sewing vinyl I highly recommend a TEFLON sewing foot (also called non-stick foot). It is ABSOLUTELY worth it's weight in gold. A total game changer for sewing stickier fabrics, including leather.
My TOP TIPS for sewing vinyl are here.