I am doing some research on what I want to do for my WLED installation. I want to use a WS2814 led strip (12V). I am using a Wemos D1 mini and found a 3.3V to 5V logic level shifter but I can’t find a 3.3V to 12V shifter nor a 5V to 12V shifter. Does anybody know one? Can I use the 12V strip with 5V signal?
Data signals for addressable LEDs are always 5V signals, independent of the supply voltage.
You use the same standard 5V shifters for 12V or 24V setups. You just connect the shifter data and ground lines to the higher voltage strip, not the V+ line.
All Addressable LEDs look for 5v Data. Data has nothing to do with whether or not you have a string of 5v, 12v, 24v, 48v LEDs Those values reference the voltage you need to (+/-) Power the string. Not the data control signal.
Your LEDs should get power from your power supply and data from your controller. Controllers output 3.3v data and LEDs are spec’ed for 5v data, so you should use a level shifter to bring that 3.3v data up to 5v. This has nothing to do with powering the LEDs.
https://kno.wled.ge/basics/getting-started/#quick-start-guide
divsys beat me 
Thank you very much. this helped a lot!