From FreeCAD Documentation
- Select the face to be bent.
- Hold down the Ctrl key (or the Command key on macOS).
- Select the coplanar sketch (i.e. lying on the same plane) containing the bend line (segments) (preferably from the tree view).
- Release the Ctrl key (or the Command key).
- Activate the SheetMetal AddFoldWall command using one of the following:
- The Fold a Wall button.
- The SheetMetal → Fold a Wall menu option.
- The keyboard shortcut: C Then F.
- Change the value of the property DataPosition to adjust the position of the bend according to the bend line.