I know you want to change the zCart branding to your own brand. You can easily customize and modify the theme to fit your brand, while still following the standards of the different platforms. You can change the logo, icon, splash screen, and all other brand-related assets that will use on your Android and iOS apps.
To know more: https://ionicframework.com/docs/theming/basics
Go to this link and select colors of your choice, basically in-app primary color will be vastly be used color all over the app. For example, green is the primary color of WhatsApp.
Upon color selection, it will automatically generate the code, which you need to copy and paste in
The app will need custom icons and splash screens images for different size devices. Luckily there is a simple way to do this. Go the the
directory and replace the icon.png and splash.png your icon and splash image. Now the assets on the place and run below command on your project root.
ionic cordova resources
This command will generate all essential assets for Android and iOS platforms.