I do not (and never had) a smart phone, either.

I have been at one restaurant that had a QR code to view the menu, although they did provide a iPad to any customer who needed it. (At the time, I was with someone else who had their own iPad.) It was not very good food (and badly managed) so I do not intend to return there in future.

If you do not want to print the menu in multiple paper copies, then you might consider a single epaper display somewhere that the customers can easily see (anyone with a camera or a camera phone can take a picture; someone with pencil and paper might copy it out by hand).