Programmed 5 Volt output to power a relay
Your concern for the output capability of the pin should be its current sourcing or sinking capability, not its voltage. Arduino pins typically have a limit of 40ma per pin and a total maximum of 200ma. This is for the Atmega328p (you didn't say which Arduino you're using. You'll need to drive motors or relays or anything else with a substantial current requirement with a driver circuit powered independently of the Arduino itself. That can be with a shield made for the purpose or a circuit you design and build into your project. Motors and relays in particular need snubber diodes to protect the driving circuits from inductive "kickback" or spikes generated in their coils.