When a pattern calls for you to mark your fabric, what do you use? A fabric pen, pencil, dissappearing ink???

The answer is simple: YES. It depends on the application and the color of the fabric.

Use your kids washable markers! I use Crayola Washable fine tip markers and it washes right out with water. The blue is stubborn so use another color.

I use an EZ international marker. It is for fabric and fades away after a few hours. It seems to work best for me.

Depends on what and where I'm marking. Since I hand piece and quilt everything, I mark the seam allowances on all of my pieces, as well as cutting lines and to do that on the lighter stuff I use micron archival markers.
I will sometimes use a regular #2 pencil with a VERY sharp point, and at times the silver or white pencils designed for quilting.. I don't trust the "disappearing" ink pens as after they had been out a short time, they were found to deteriorate the fabric. Just left me uncomfortable, so I didn't use them.