You find an Online printer service, send 'em your drawing as pdf, jpeg or whatever they specify, and tell 'em what size you want the final print, and they'll post it to you.
If you're lucky rolled up in a toob!
Personally I've never needed to bother.
I scale plans with a 2D drawing app and printout on an A3 printer/scanner.
Two A3 sheets gives a max length of 33", three sheets 49.5". With 'borderless' printing.
One A3 sheet is generally enough for the frames.
A3 scanner / printers are pretty cheap these days.
Cost a small fortune not so long ago, then I fiddled about joining up loads of A4 sheets 🤔
Cheers, Doug 😎