How i can change the Staff Icon

[Canapin (Coin-coin le Canapin)]

Not sure if that can help, but maybe you can have a look at this:

Replace Discourse's default SVG icons with custom icons in a theme

You can replace a Discourse’s default SVG icons individually or as a whole with your own custom SVG and override them within a theme or theme component. Step 1 - Create an SVG Spritesheet To get started, you must create an SVG Spritesheet. This can contain anything from a single additional custom SVG icon up to an entire replacement set of hundreds. The spritesheet should be saved as an SVG file. In principle, you are nesting the <svg> tag contents from the original SVG icon file into <symbo…

Introducing Font Awesome 5 and SVG icons

We will shortly merge into master a branch that upgrades Discourse to Font Awesome 5.5.0 (the free version) and switches to using SVG icons instead of an icon font. This is a substantial change, with lots of benefits, and one significant change for developers. Here is a quick rundown of the changes: using SVG icons will provide crisper icons, better for accessibility and easier to customize, see this Github article for more details since the Font Awesome icon set has grown to 1300+ icons in v…