Bring Text to Life with Godot's BBCode & RichTextLabel
Godot's RichTextLabel node is a text renderer that understands a subset of BBCode - a markup language using [tag] and [/tag] delimiters.
It's the go-to choice for dialogue boxes, item descriptions, tutorials, and any UI text that needs more than a plain string.
To enable BBCode, set bbcode_enabled = true in the Inspector or in code.

Then assign your marked-up string to the text property.
"[b]Hello[/b], [color=cyan]world[/color]!"

But it can go beyond mere text formatting. It can be used to generate Text Effects that generate animated text.
[pulse freq=1.0 color=#ffffff40 ease=-2.0]Pulse Effect[/pulse]`
But the real power of this tool is creating our own Custom BBCode tags.