In Webflow, Components are building blocks that help you maintain consistency across your website. When you need to update a navbar component, for example, you can update the component once, and everywhere that navbar components exists on your site is also updated.
But sometimes you need a bit more flexibility — you want to maintain design consistency, but you might need one instance of a component to contain something slightly different. That's where Component slots come into play. With slots, you create a placeholder within your component, and later, when building your site, you can decide what other components to put into that slot. This way, you get the design consistency of components, but enough flexibility with slots to adapt on different parts of your site.