Most wifi printers will support the printing from an iPad or Android device but the trick is to make sure that the printer is connected to the wifi network first.
When setting up the printer you need to get it to see the wifi network and connect to it.
Then you need to get your computer to see the printer through the network and your router.
Your iPhone or iPad will then see the printer through the network and your Android device will be able to see the printer when you have downloaded the printer companies app from the Google Play Store.
if you do not have wifi then look for a printer that has WIFI Direct then your device will connect to the printer