The following constructions using party are commonplace: Acme is a party to a confidentiality agreement with Widgetco dated October 7, 2007.

Is party an adjective or adverb?

Although it's almost certainly not what the worksheet is looking for, there is one definition in the OED for "party" as an adverb (it just means "partly"), which is marked as "Now rare (only in Heraldry)".

Is party a noun verb or adjective?

party (noun) party (verb) party animal (noun)