Look for “Airprint” capable printers.
If it has Airprint, then it will work with your iPhone/iPod Touch/iPad devices.
If you are printing using the computer, then a wired connection to any printer will work fine.
Printers brands have differing models and availability. Ask the support team if you have a model in mind.
Here's a list of printers from Apple. We also compiled a list from the past years here.
If you have a wireless-printing printer lying around where you can print using their app but is not AirPrint capable, then it's possible to export the note from SeriousMD and print it through their app (HP Smart, Epson, Brother, Canon App, etc) - it's just an extra step of exporting and another extra step to switch apps.
For 2018, we recommend the following locally available printers:
Brother DCP T510W
Brother DCP T710W
Brother MFC T810W
Brother MFC T910DW
With an Airprint printer, you'll be able to use it wirelessly with your Apple devices, and it also works when wired directly to your computer.