It depends on the MD program you use. It is possible to write restart files in some of them (e.g LAMMPS) which can be used to resume simulations. Less precise method for restarting a simulation is to use last frame from a trajectory file as a starting point of the next run. This, however, can be done only if both atom positions and their velocities are saved.

@Deepasree K.P You can try the following command

gmx mdrun -deffnm md_0_1 -cpi md_0_1_prev.cpt -v

It worked Sunidhi Bhatt . Thank you so much.