Cut sheet labels are provided cut down to the final finished size ordered. For example, if 2x3 labels are ordered, they will be cut down to 2x3 individual labels. They will not be provided as a certain number on a larger sheet but as actual individual labels. The liner sheet of these labels is thicker and usually has cracks or slits in it, so a small part can be removed, leaving the rest of the liner. This is because these are intended for application by hand.
Roll Labels are provided, as the name suggests, on rolls. The liner is thinner and more flexible than cut-sheet labels in order to wrap around the core and does not have cracks on it. Roll labels are usually applied with a label application machine, though can also be applied by hand. The standard is for rectangle or square labels to be provided with rounded corners to prevent the corners from peeling off and getting snagged in the application process or once applied to the product (ie when the product is inserted into a box or when the customer is handling it).