Why do we need to input a billing address when purchasing online? Can this step be removed from the checkout process?
Is 'shipping address' sufficient?
The website only sells to individuals and not businesses.
I would advise strongly against removing the step, but to add it as optional step instead. There are a lot of reasons why the billing and shipping address could differ, e.g.
That being said, here's the main reason why you need the billing address at least as an optional step:
A lot of companies use the Address Verification System to match the entered address against the cardholder's address (assuming a Credit/Debit Card payment takes place). By stripping the possibility of providing two different addresses you're most likely also stripping the possibility to do the transaction in the way the user would like to do it and would force the user to send the goods to their billing address.
This of course only applies if you're accepting credit/debit card payments.
This is a "Depends" answer but I'll explain why.
I'm with you, 99.99% of the time all I care about is a shipping address. However I never ship stuff to my home.
Almost everything I get delivered gets delivered during business hours - when I'm at work! So to avoid any missed deliveries (or stolen packages from my porch) I get everything delivered to my office at work.
However there are some things I buy online that send a physical "paper mail" receipt, bills etc. to me as a separate item... so I get those sent to my house as part of "regular mail".
Thus my preference when ordering online is to have 1 shipping address, then if the company so desires, offer a pre-checked "Billing address same as shipping address" checkbox. If I so need to alter it, I can do so. (I'm fine with the reverse to, either way as long as I don't need to enter the address twice! if I'm using the same address)
However in your case if the bill is shipped with the item to the address, then I don't see an issue (as a user) if there is only the shipping address.