Everyone has a fave way to do foundation piecing. My least fave is using any type of paper that needs to be removed. Some people leave it on but when you wash it, it gets kinda balled up and noisy even. It was so messy to rip out paper and it made some of the stitches come loose. Once was enough, now I use a fabric foundation.
My fave way is to use the most inexpensive muslin I can find and on sale OR I've used some thin ugly fabric from my stash (I would not use it for a quilt top or backing) and stitch the strings etc to the wrong side, so it is least likely to show thru to light colored fabrics.