If you delete files or folders from your myCloud folder or directly from myCloud.ch, these will be moved to the corresponding recycle bin / trash. Files located in the trash will no longer be synchronised between your devices.
You can find more information about permanent deletion here.
Please note: if you delete files from your trash on your computer, these will not automatically be removed from the trash bin at myCloud.ch. Thus, you’ll still have a copy of your files even when you completely remove them from your devices.