The 'bleed' lines around the edge of the card are for reference only and will not appear on the final result. The purpose of the bleed line is to make sure you allow a small margin of tolerance if you plan to send your project for professional printing. Professional printers will require this margin, because there is a small tolerance of variation in trimming when they cut the printed output. If you do not provide this margin, some of your text might become 'clipped' as they are trimming. However, as long as you keep your text inside the 'bleed' lines, you will be sure to be safe.