How do I build a PCB heater that turns off/on with a remote control

 

Huge heap of questions here. Are you asking for someone to design the whole thing for you?
This is why no-one is answering.

 

Please define "pcb heater"...
Are you talking about a reflow oven? or a PCB based heating pad like for the base of a 3d printer? or what?
And obviously you need to specific voltage/current/wattage/temperatures/size,etc... and any/all other specifications/requirements you want.