In the Checkout page, a buyer will be asked for their contact information and the address fields are mandatory for payment providers and realtime shipping calculation to work properly. Do not disable Country and Email fields, leave them as mandatory. Other fields can be set as optional such as "Your notice to us" field. 

1. Open your shop in ShopFactory.

2. Click "Central" dropdown from the toolbar -> Customer Details 

3. Customer Details dialog shows up and the first form is "Billing Address".

On the left pane , you will find the List of Fields.

All the fields that are ticked are displayed on the Order Form at Checkout.

To remove from the Order form untick it.

4. To make a field available on the Checkout Order Form but optional (not mandatory), select the field and click Edit button.

For example I want to make "Your notice to us" field NON-Mandatory but I still want it to appear on the Order Form -> untick "This information must be provided by the customers" checkbox and then click OK.

5. Click Next. Repeat step #4 for Delivery Address fields if needed.

6 . Click FINISH.

7. Save and Preview your shop.

8. Place a test order to see changes, when happy with the changes publish your shop.