Yes. Here's how:
- Select the Colour tab in the left panel, to change the existing background colour of a Sticker.
- Change the sticker's background colour by:
- Selecting one from the colour palette
- Selecting via the Eyedropper Colour Tool
- Specifying a custom colour or adjust the CMYK values
- You can also choose to have a transparent background by choosing the No-Colour option, i.e. the white circle with a redline in it.