This article describes how to change the colours and images (logo, icon etc) on your coupon to match your own branding.
To personalise the branding of your pass in the designer, just click on the theme icon situated at the top left corner. From there, you can select your preferred background colour and switch between Google Wallet and Apple Wallet to preview how it will appear.
If you're using Google Wallet, you only need to provide one colour value and Google will apply a theme for you.
However, with Apple Wallet, you can choose the background colour, label text colour and value text colour to create a custom theme that suits your needs. Click on “Save” when you are done.
From here you upload new images for your design also.
Remember, you can always change the images and colours on your pass using the designer at any time.
Further reading,