In this work, the problem of the approximation by certain polynomials is addressed. A new type operators sequence including generalized Appell polynomials are defined, qualitative and quantitative approximation theorems are proved. Some explicit examples of our operators involving Hermite polynomials of $v$ variance, Gould--Hopper polynomials and Miller--Lee polynomials are given. Also, we present some numerical examples to confirm our theoretical results.