as a conjunction (connecting two clauses or phrases): We shouldn’t spend more than we earn.
as a preposition (followed by a noun): I’m taller than my dad. (followed by a number): A crowd of more than 10,000 had gathered. Object pronouns are normally used after than: He was three years older than me. Some people think that it is more correct to use subject pronouns after than, but this sounds very formal and old-fashioned: No one could have worked harder than she.
Than is used especially after a comparative adjective or adverb.