The A4ScanDoc program supports double-sided scanning.To do this, in the "Scanner Settings" section, you need to enable the "Auto Feed Tray (ADF)" and "Double-Sided Scanning" options.
If there are blank sheets in the stack of documents that should not be included in the resulting file, you can set the "Skip Blank Sheet" option.
If you want to save a scan copy of a document in a multi-page file, you can choose the PDF or TIFF format.
More information about the AScanDoc program can be found on the official website
https://a4scandoc.com