The goal of this study is to analyze the impact of Casson fluid, physical parameters, and suction/injection on two‐phase mass transfer effects on unsteady magnetohydrodynamics flow over an elongating surface in the presence of thermal radiation and viscous dissipation. The system of nonlinear ordinary differential equations of flow, energy, and mass transfer are developed and computations have been carried out through the shooting method along with Runge–Kutta fourth and fifth‐order techniques. The graphs and tables are depicted and explained for the response to various embedded parameters. The C italicfx ,   N u x ,   and   S h x ${C}_{{fx}},\unicode{x02007}N{u}_{x},\unicode{x02007}\mathrm{and}\unicode{x02007}S{h}_{x}$ are also analyzed for distinct values of A , M , R , Pr , Sc , Ec , and   Cr $A,M,R,{\Pr },{Sc},{Ec},\mathrm{and}\unicode{x02007}{Cr}$. The observations of this examination are well detailed in the present research.