Embroidery makes many, many more stitches in the fabric than sewing seams. This can cause the background fabric to bunch up and pucker, as it cannot support the heavy stitching.
A stabiliser under the fabric gives the additional support needed to hold the stitches and to prevent puckering whilst being worked, giving an even, flat and smooth result.
We have a link to OESD who have an article to help you select the correct stabiliser. Click Here. We stock the full range of OESD stabilisers. Click Here.