Hello Chuh00,
"Address" is your home address or the address of the building or house where you want the package to be sent to ,it could be the company where you work for....etc
Whereas the post address is the mailbox postal number ,including the postal code of your country. DHL will deliver the customer's order to an agreed destination be it your own address ,any other address or a mailbox. So you will need to write the address ,where you want to receive your package.