Crayon emoji along with ✏️ Pencil emoji is the picture of an item, which is typically used for drawing things (it’s red, pink, blue, or green, depending on the emoji provider). It is used in the context of drawing pictures and marking something. Also, crayons are especially popular with children — so the emoji may be also used in the meaning of childhood and being childish.
Examples of using
“I loved crayons when I was a child 🖍”
“I like making sketches 🖍”