From the Help > About this window on the Purchase Requisition Entry window, it states the following for the 'Ship To Address' field:
Ship To Address
Select the company address to send the requested items to. A shipping to address is not required for the requisition.
An icon will appear on the Ship To Address ID field if the address information has been changed for the requisition.
You can click the Ship To Address link to open the Company Address Setup window.
Ship to Address ID expansion button
Opens the Purchasing Ship To Address Entry window, where you can modify or view the ship-to address information for the requisition. Any changes you make will apply only to the current requisition.
Ship To Address (scrolling window)
Enter the address ID for the ship-to address.
For an inventoried item, the default ship to address ID associated with the site ID entered.
If the site ID is blank, then the default address is from the requisition header.
If the shipping method is delivery and Inventory Control is registered, the default ship to address comes from the site.
If the shipping method is delivery and Inventory Control is not registered, the default ship to address comes from the requisition header.
If the shipping address is pickup, the default ship to address is from the vendor’s purchase address.
If the shipping method is blank, then the default ship to address is blank.
For a non-inventoried item, the default ship to address ID for the line item is the address ID you entered for the document header. TMN - If the method is pickup, then, the ship to address ID on the line should default from the vendor
An icon will appear on the Ship To Address ID field if the address information has been changed for the current line item.
Ship to Address ID expansion button
Opens the Purchasing Ship To Address Entry window, where you can modify or view the ship-to address information for the item. Any changes you make will apply only to the current line item.