The Checkout lets you use the customers' shipping address as the billing address by default.

Follow the steps below to set it up:

Step 1: Go to the 'Design' tab

Scroll down to the Checkout Form Fields.

Step 2: Rearrange the address fields

Drag and drop the "Billing Address" fields ahead of the "Shipping Address" fields.

Step 3: Enable the option to enter a different shipping address

Click on the 'Shipping Address' field.

Scroll down to the bottom of the list.

Click on the eye icon beside the option - 'Use a different shipping address'.

Make sure the field is visible and not hidden.

Next, click on the 'Update' button.

This will update the changes.

Final Output:

This is how you can set up the form with billing details instead of shipping details.