Do you want to use paper backed fusible ( like heat n bond lite or steam a seam and machine appliqué?) or do you want to do hand appliqué?
hand appliqué people often use freezer paper ( not waxed paper-freezer paper in the blue box at the grocery store) to create their appliqués. Machine appliqué you can use a fusible. Either way you trace your shapes on the paper. Freezer paper you use the drawn shapes as your template press the shiny side of the paper to the right side of your fabric, cut out adding seam allowance, turn under edges & hand stitch in place. Fusible/ machine appliqué you reverse the images draw on the paper side of the fusible. Press the fusible to the wrong side of the fabric, cut out the shapes, peel off the paper, fuse to the background then machine stitch in place.
People get their appliqué shapes/ designs from any number of places...coloring book pages, photos, hand drawn designs, commercial patterns, clip art, the sky is the limit.