Typography plays a crucial role in both UI (User Interface) and UX (User Experience) design. In UI design, it's used to communicate information, guide the user through the interface, and establish the overall visual style of the product. Good typography in UI design enhances the usability and accessibility of the product by making text legible, readable, and scannable. In UX design, typography affects how users perceive and engage with the content, as well as how easily they can find and understand the information they are looking for. This can influence how users process the tone and personality of a brand, as well as its credibility and trustworthiness from the information it provides. Overall, typography is an essential aspect of both UI and UX design that can have a significant impact on the success of a design by making it more usable, accessible, and appealing.