How does Captain Phasma type her password to deactivate the shield protecting Starkiller Base when she is wearing thimbles on her fingers?
Because she doesn't type to do it (in the film)- it appears to be a dial / handle.
Finn never indicates she should type in a password, he simply says:
FINN You want me to blast that bucket off your head? Lower the shields. CAPTAIN PHASMA You're making a big mistake. FINN Do it.
You can see that there is no standard keyboard on this particular control panel
This is addressed in the film's tie-in novelisations. Apparently the lowering of the shield was accomplished by pushing buttons rather than typing commands on a keyboard.
Chewie backed him up with a roar.
As Phasma pushed a few buttons, Finn looked at Han. “Solo, if this works, we’re not going to have a lot of time to find Rey.”
The sequence did not require extensive typing.
He planted Phasma at a console and ordered her to initiate the deactivation. When she refused, he pressed his blaster harder against her helmet. “Do it.”
She did. A few keystrokes were all it took to bypass the automatic systems and start the sequence to shut down the shields.