Adobe's web font service is a tool that allows designers and developers to use a wide variety of fonts on their websites without needing to host the font files themselves. This service provides access to thousands of high-quality fonts from the Adobe Fonts library, which can be easily integrated into web projects through a simple code snippet. By using Adobe's web font service, users can ensure that their websites maintain a consistent look across different devices and browsers. The service also offers features like font pairing suggestions and the ability to customize font weights and styles, enhancing the overall design experience.