On the HSK 4 vocabulary list, at CEFR level B2.

tóu ㄊㄡˊ

    • to throw (sth in a specific direction: ball, javelin, grenade etc)
    • to cast (a ballot)
    • to cast (a glance, a shadow etc)
    • to put in (money for investment, a coin to operate a slot machine)
    • to send (a letter, a manuscript etc)
    • to throw oneself into (a river, a well etc to commit suicide)
    • to go to to seek refuge to place oneself into the hands of
    • to rinse (clothes) in water

      coll.

Where 投 is used

Sources