Rolling your quilt onto a tube is the ideal storage choice. Taking the quilt, roll onto the tube with the right side facing out. Cover with a cotton sheet or cloth. If it is not possible to store the quilt rolled onto a tube, boxing would be the next best choice. As much as is practical, avoid folding your quilt.
Folds can place permanent creases within fabric that are impossible to remove.
Folding can also stretch the individual stitches and fibers within the quilt. If you have to fold your quilt, pad the underside of the fold to make a relaxed fold, avoiding any sharp folds. Stored quilts that have been folded should be unfolded and inspected for damage at least once a year. Never place the fabric in direct contact with wood. By making sure your quilt is clean, that your hands are oil and lotion free when handling and choosing the best possible environment for storage, you will have gone a long way to ensuring that you have a treasure that can be passed from generation to generation.