File | Settings | Editor | General | Code Folding for Windows and Linux
PyCharm | Preferences | Editor | General | Code Folding for macOS
Ctrl+Alt+S
Use this page to specify the default code folding settings. For shortcuts on how to expand or collapse code elements, refer to the code folding section.
Item
Description
Show code folding outline
Select this checkbox if you want the code folding toggles to be shown in the editor. Clear the checkbox to hide the toggles.
Fold by default
Select the code fragments which should be folded by default, that is, when a file is first opened in the editor.