他

Left radical 亻 is the side-form of 人 (person). It marks 他 as a person-pronoun: 'he' or generically 'that other one'. The person radical groups 他 with the pronoun-trio 他 (he), 她 (she, with 女), 它 (it, with 宀) — all built on different right-sides to distinguish gender and animacy.

Right phonetic 也 supplies the sound — yě shifted to tā through long-distance onset drift (originally 也 itself had a t-like onset in Old Chinese). 也 originally pictured a wash-basin or coiled snake. Same phonetic in 她 (she), 它 (it), 池 (pond), 地 (earth) — all sharing the historic onset that has split into modern t/ch/d.