M7

Good day
clould any tell me what do i need to change Siemens M7-388 CPU to new S7 300 CPU ,what about the application program and the other things i need to take care off

The bad news is that there is probably no directly compatible or even slightly similar CPU.
As far as I know, M7 program were written in Borland C. The compiled code cannot be read out from the CPU as a PLC program can.

Do you have the original source code of the program ?
If so, that could be the basis of reverse-engineering a new PLC program on the basis of the M7 program.