In this research, we leverage various $q$-calculus identities to introduce the notion of $q$-Hermite-Appell polynomials involving three variables, elucidating their formalism. We delve into numerous properties and unveil novel findings regarding these $q$-Hermite-Appell polynomials, encompassing their generating function, series representation, summation equations, recurrence relations, $q$-differential formula, and operational principles. Our investigation sheds light on the intricate nature of these polynomials, elucidating their behavior and facilitating deeper understanding within the realm of $q$-calculus.