In the screenshot below there are three steps (1-3) that can be removed from the Checkout page
To remove Step 1 go to Configuration > Settings > Order Settings and tick the checkbox next to 'Skip Billing Address Step'. Note this will only remove the step from the customer's checkout page if there is already a Billing Address assigned to their account
To remove Step 2 go to the products you wish to apply this to in Catalogue > Products > Manage Products. Navigate to the product variant page through Product Variant > Edit, un-check Delivery Enabled. If this is for the entire storefront then apply this to all products
To remove Step 3 go to Configuration > Settings > Order Settings and tick the checkbox next to '