Small kids at their initial stage love to move pen and pencil in to and fro or up and down position. This way of writing is _________

The to-and-fro, up-and-down marks made by young children with pen or pencil are called scribbling. Scribbling is the earliest stage of writing development where children explore mark-making. Drawing involves representational intent, invented writing involves letter-like forms, and zig-zag is just a pattern type—scribbling is the correct developmental term.