actual address is Different from the billing address on my ticket

No. People have multiple addresses and sometimes companies pay for tickets for employees and the billing address will be different. The billing address is generally used for verification during the transaction which is why there is a separate set of fields for billing info. In some cases, you have a check-box or default when registering to make all addresses the same. You can usually fill in your contact details on the airline website and you may be asked during online check-in, if you have not done so by then.