Here is a way to make one (M1) in knitting without producing a hole where you did so. Like most knit or crochet stitches, it has been given many other names as well.
The M1R, in particular, is useful almost anywhere that you encounter instructions to simply “make one.” The M1L is also useful when you need to add a stitch at the very end of a row.
Click on each photo for a larger image. Happy knitting! 
