Depicts a person (勹) hugging a child (子). Based on the original meaning "to embrace", now written as 抱. The meaning later shifted to "cover" and "wrap".
Shuowen Jiezi
《說文》：“包，象人褢妊，巳在中，象子未成形也。”
Original meaning
to embrace
Components
勹(sound, iconic) — Depicts a person hugging. 勹 also represents the sound.
子(iconic) — Depicts a child. Modern form looks like 巳.