Devices, Methods, and Graphical User Interfaces for a Unified Annotation Layer for Annotating Content Displayed on a Device

An electronic device with a display device displays a user interface that includes content. The electronic device, while displaying the user interface that includes content, detects a first input. The electronic device, in response to detecting the first input, displays an annotation layer over the displayed content. At least a portion of the content is visible through the annotation layer. The electronic device, while displaying the annotation layer, displays a set of markup tools, including a plurality of tools for adding marks to the annotation layer. The electronic device detects a second input selecting a first markup tool of the set of markup tools. The electronic device adds one or more marks on the annotation layer in accordance with one or more additional inputs using the selected first markup tool.