This QR Code library supports encoding a a string to a QR Code image.
$ dotnet add package MH.QRCodeEncoderUse this to encode a string to a QR Code.
...
services.AddQRCodeEncoder();
...
var encoder = serviceProvider.GetRequiredService<QRCodeEncoder>();
var stringData = "test";
encoder.Encode(stringData);
encoder.SaveQRCodeToPngFile("qrcode.png");