Shopkeeper does not have a dedicated iPhone app, but you can set up a convenient bookmark icon, which will look like this:

To set this up, follow the steps in the video below:

STEP 1: Open Safari and navigate to https://shopkeeper.com/dashboard.
STEP 2: Click on Share Button:

STEP 3: Click 'Add to Home Screen' button:

Then save, and you will have a nice app-looking button on your home screen to check your daily sales.