Because i am a big fan of structure and minimalism i remove all Apps from my Dock. There is only Finder (because it is mandatory) and custom folders for different kind of Apps. Therefore i created custom folder icons with Affinity Designer and Font Awesome (this Affinity Assets package came in quiet handy).
- Select the image file and press CMD + C to copy the image
- Open the location of your Folder in Finder
- Right-click --> get Info
- Select the icon in the upper left corner and press CMD + V