First: It's HTML :P
Second: It's honestly easy as fuck.

The basics is taht you have to start off with a general form.

<c val=" Color code here.">The colored characters here.</c>

The "c val" is the part of the code that is rad as "This will change the color of the characters". Then it has to equal something in order for it to change so teh equals is added. To read a color you need a color code. The codes range from numbers 0 to F with six characters. You can find things on the internet (Try and find a pallet) that can convert colors into HTML codes for you. This will simplify your work. Once you have the color code inserted you need to specify that it is indeed that color by putting it in quotations, a form generallyused in coding to specify something. Then you close the code, and show what needs to be changed. You close it the same way you open it. With a < > format. Then you enter what will be colored with the color you chose. You can make just one letter (This is how a gradient name is done) or the whole name (For a solid color). You then need the end the name to leave room for another code so you use </c> as in "end coloring". This was a somewhat simple explanation as to what you do, and why you do it.

All you need to do is find a pallet, in fact here's one that I use: https://www.computerhope.com/tips/tip143.htm

In the pallet you find the color desired and it will show the color code that displays that color in the bottom right corner of the pallet.

Just start off with the simple form <c val="123456">Sookie</c> and find the color desired for the name using that pallet, and replace that "123456" with that color (Remember the quotations!)

For a gradient you need multiple codes. Because you need to designate a specific color to each letter. You can do this by opening another code directly after closing the one before it. If you put a space between them, or a space after/before the letters that are being colored, you will ahve a space in the name. To make a solid name with multiple colors you need them to be close, like this:

<c val="123456">S</c><c val="123457">o</c><c val="12358>o</c><c val="123459">k</c><c val="123450">i</c><c val="123451">e</c>

I don't know what those colors are, but if you want a gradient name just replace the "123456" and all that to the codes you want.

I hope this helps you, and I hope you enjoy your colored names :3