Change colors of sign text in MCBE

You can colour text anywhere the section sign § is accepted, which is any text input. So that means, you can colour text anywhere you can enter text!

To colour text, place the section sign § before the text to colour, followed by one character. This character will not be shown and determines the colour to use.

Examples

§aHello, World!

↓

§aHello, §9World!

↓

See the table below for possible colours.

Therefore, to colour sign text, just type it into the sign:

An interesting quirk is that line breaks reset the formatting on the sign, but not in the text input. See the image?

Learn more about Formatting Codes on the Minecraft Wiki: Link

Can you enter custom hex codes?

No.

Why is that? Well, we need to take a look at how you would colour text in Java Edition, which uses JSON text.

Here is how you would colour those same two examples in Java Edition:

{"text":"Hello, World!","color":"green"}
[{"text":"Hello, ","color":"green"},{"text":"World!","color":"blue"}]

Now, notice the name for the colour green? Those are the colour names in the table! So in Java Edition, you give a colour by the name, not by code letter.

To type in a hex code, you can replace the colour name by the hex code, like this:

[{"text":"Custom Colours","color":"#FF0F0F"}]

Now, in section sign formatting codes, there is only room for one letter to specify the parameter. How are you supposed to type an entire hex code?

With the current system, it wouldn't be possible. But who knows, maybe someday there will be a system overhaul and this will be possible.