收税 is a verb-object compound (离合词) meaning 'to collect/levy taxes'. It acts like a two-character verb, but the object 税 ('tax') can separate from 收 ('collect') when you need to insert a measure word, duration, or other modifier — for example, 收了三年税 ('collected taxes for three years') or 收过两次税 ('collected taxes twice'). You do not put a direct object after the whole word; instead, use a location or scope like 对公司收税 ('collect taxes from companies').