Configuring Project Structure
To access project structure, open Settings / Preferences Dialog by pressing Ctrl+Alt+S or by choosing for Windows and Linux or for macOS, then expand the Project node, and select Project Structure.
In PyCharm, content is a collection of files with which you are currently working, possibly organized in a hierarchy of subfolders. The top-level folder of a project is its content root.
Within a content root, PyCharm can distinguish between the folders that contain source code, and the ones to be ignored while searching, parsing, watching and so on. To distinguish different types of folders, mark any folder below a content root as a source folder or as excluded.
Source roots contain the actual source files and resources. PyCharm uses the source roots as the starting point for resolving imports
Resource roots are intended for resource files in your application (images, Style Sheets, and so on). By assigning a folder to this category, you tell PyCharm that files in it and in its subfolders can be referenced relative to this folder instead of specifying full paths to them.
Template roots contain templates for the various web projects.
Excluded roots contain files and folders ignored by PyCharm when indexing, searching, parsing, watching, and so on.