Folio does not delete your emails. If you delete a Smart Folder, the folder's label will be removed from your emails, but your emails will not be deleted.
Gmail: We do not move your emails out of your inbox. Folio uses Gmail's built-in labeling system to categorize emails into Smart Folders, but you will always be able to find them in your inbox as usual.
Microsoft 365: If you enable email organization in your Folio settings, we will move emails out of your inbox and into Folio folders in your Microsoft account.