See https://github.com/rugk/offline-qr-code/wiki/FAQ#how-to-save-the-qr-code-on-disk for how to save the QR code as an image file. You can then use any software to further edit or print the QR code.

As for Code128 there is currently no intend to add other data code modes. As far as I see Code128 can also only encode numbers and ASCII characters making it quite limited in contrast to QR codes, which are also more widely supported.

If you have further issues or questions, feel free to ask or suggest a feature by opening an issue on https://github.com/rugk/offline-qr-code/issues. Thanks.