In your BigCommerce management console navigate to Advanced Settings on the left menu.
From here select the API Accounts towards the bottom of the list.
Then you'll need to click the blue 'Create API Account' button, then click 'Create V2/V3 API Token'.
Now you can name your new API link. The name needs to be Frooition Design widgets
You then need to change the CONTENT and THEMES selections to show as 'Modify'.
Once this has been done you can send us the .txt file over as normal.
This video will run you through the steps in real-time, if you have any issues please contact our support team or your designer.