投 is versatile: 投票 (vote), 投资 (invest), 投诉 (complain), 投降 (surrender), 投篮 (shoot a basket). The core sense is throwing or directing something toward a target.
Left hand radical — simplified 3-stroke form of 手. The indexing radical. Throwing, casting, and pitching are all hand actions, so the radical is literal. Same radical heads 抛, 扔, 拿, 推 — the family of hand-driven verbs.
Right 殳 — a hand 又 below holding a forked weapon. Reinforces the throwing meaning: 投 originally pictured a hand hurling a spear, two hand-shapes side by side emphasizing motion. Same component anchors 段, 殴, 般, 役. The whole char is indexed under Kangxi #64 手 (shǒu, hand) — the 扌 on the left.
