If you have a usb-c ac adapter from a laptop these are nice to use for prototyping. There are some out there that you have to solder the selected voltage in place, Another one has an onboard chip that allows you to select the voltage by the press of a button.  I prefer the dip switch setup. Just always verify using a multimeter.

USB Type-C QC AFC PD2.0 PD3.0 to DC Spoof Scam Fast Charge Trigger Polling Detector USB-PD Notebook Power Supply Change Board Module

PD/QC/AFC  fast charge decoy trigger

Support 5V 9V 12V 15V 20V fixed voltage output

Voltage regulation: According to the table on the back of the board, adjust the dip

switch to control the voltage output.

Since there is no voltage indicator after adjusting the dip switch, use a multimeter to measure the voltage before connecting to the application circuit.