Help is here.

Can I customize the background colour of my Sticker?

Yes. Here's how:

  1. Select the Colour tab in the left panel, to change the existing background colour of a Sticker.
  2. Change the sticker's background colour by:
    1. Selecting one from the colour palette
    2. Selecting via the Eyedropper Colour Tool
    3. Specifying a custom colour or adjust the CMYK values
    4. 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.