Vcc in vs Output voltage

I need clarification since I've read conflicting information.

If I power Arduino with 12v at Vcc in what should the output pin voltage be 12V or 5V?

If I'm getting 12V on the output pins of my board did I damage the board?

You didn't specify what Arduino exactly.

duinoMike:
If I power Arduino with 12v at Vcc in what should the output pin voltage be 12V or 5V?

Depending on Arduino itself some boards may accept 12 as Vin (special pin that goes to 5V/3.3V voltage regulator).

duinoMike:
If I'm getting 12V on the output pins of my board did I damage the board?

Most likely yes.

Its an Arduino Uno R3 by Elegoo.

If you apply 12V to Vcc (5V) on an Uno you will probably get a smoking hole in the processor. Apply 12V to Vin and the 5V regulator will output 5V and about 150 mA maximum. The best way is to use a DC-DC converter to drop the 12V to 5V and apply that to the 5V input, bypassing the weak 5V regulator.

The output voltage on a pin depends on the load on the output pin. If the pin current is less than the recommended maximum of 20mA, the output voltage will be very close to Vcc. More current wil result in lower output voltage.

groundFungus:
Apply 12V to Vin and the 5V regulator will output 5V and about 150 mA maximum.

Lacking a heat sink I don't think that regulator gets close to 150 mA for any useful period of time. That's over 1W of dissipation!

Lacking a heat sink I don't think that regulator gets close to 150 mA for any useful period of time. That's over 1W of dissipation!

All the more reason to not use the on board 5V regulator. The DC DC converter will dissipate much less power and make more current available on the 5V rail.

The fact the OP’s seeing 12V on the output pins, could indicate they’re not using a common ground/0V across the setup while measuring.
Everything floats up to the supply rail until something doesn’t - then there’s a likelihood of papal smoke.