You can sketch out your board in KiCad [0] and export it as a gerber that you can send to a printing service. CERN uses it now, so it's worth learning, as it'll only improve over time. As for PCB shops, I'd start with comparing [1] [2] and [3], and seeing which has the best price for your needs. Generally, just searching reddit for "PCB prototype manufacturer" will get you a couple decent options. It really depends on how complicated your design is and how big of a run you need.

[0] https://www.kicad.org/ [1] https://www.pcbway.com/ [2] https://jlcpcb.com/ [3] https://oshpark.com/