Saving code to LED strip

I have coded some colours for the WS2812B and works perfectly. I want to save those settings into the LED so they can work independently without the UNO or the circuit board. Just like the LEDs we get online which work with IR remote and pre-saved settings.

Is there a way for me to get like a controller where I can save the code and connect power supply for LEDs to work independently?

The WS2812B doesn't have any capability to do that, you need some brains for each one or for each strip. You can use a Promini to control them, it is pretty small and easy to integrate into your project. Get an FTDI Basic (or clone) so you can connect a PC and download code into it. It has the same processor as the Uno, so if your code runs on the Uno it will run the same on a Promini.