The default font size is usually small enough to minimize distraction, but you can experiment by changing their font size and placement to make sure. Make sure your header and footer don’t make your presentation look cluttered.
Use the masters to place header and footer information on your slides, handouts, or notes pages. They often include information such as the presentation title, slide number, date, and name of the presenter. You can choose to not have them appear on the title slide. Headers and footers appear on every slide.
Learn More Buy Adding a Header and Footer