You need to have a Shipday account in order to connect with Shopify.
2. If you are not registered, create a new account at https://dispatch.shipday.com.
3. After logging into Shipday Dashboard Click the Integrations section on the top right corner of the screen.
4. From the Integrations page Click the API Credentials button.
5. Click the Show API Key and then Copy API Key button and copy the API Key into your clipboard.
6. Now go to your shopify admin Shipday: Delivery + Pickup app, Click Settings, then Connect with Shipday account
7. Place the already copied API Key into the textbox and hit Save.