I have a use case where we must include a QR code in receipts generated for tax payers. The app has been built in SharePoint 2019. I see NWC has a QR code generator, but (as far as I can tell), there is no way to get the QR code image or, alternatively, the generated receipt into SharePoint 2019 from NWC. I tried the below REST API but it requires the contents of the file be converted to binary I believe. Anyone who can help me out will be a life saver.

https:////server]]/sites/s/site]]/_api/web/GetFolderByServerRelativeUrl('('folder sever relative URL]]')/files/add(url='='file name with extension]]',overwrite=true)