Pico Supply Voltage

The specs say "On-board 3.3v 250mA voltage regulator, accepts voltages from 3.5v to 16v" You can check out the schematics and board files

Wasn't 100% sure about the pins, but Gordon said in an earlier post:

The Pico itself will run direct from the car's 12v though (it'll do up
to 16v, so fine while the engine is running too). Just connect it
between the VBAT and GND pins (opposite sides of the board to each
other).