The differences on the options you are getting in the sales tax settings are,
A resale number allows your business to avoid paying sales taxes on items purchased for resale to customers. A tax ID number, on the other hand, identifies your business in your dealings with tax agencies. Resale numbers are the responsibility of state governments, while tax ID numbers are issued by the federal government.
You could use it, as it's just for information and isn't used anywhere else in Quickbooks.