changing path in a for loop?

I am trying to use a for loop for doing some task in different folders. So, I use the cd command to change the current path in each iteration. But I realized that the path to be put in the cd command can't be a variable. How could I deal with that?

[Stephen23]

"...the path to be put in the cd command can't be a variable"

Of course it can be:

https://www.mathworks.com/help/matlab/matlab_prog/command-vs-function-syntax.html

But the much better approach is to use absolute/relative filenames rather than slow and difficult-to-debug cd. All MATLAB functions that read/write data files work with absolute/relative filenames.

[Abdelrahman Taha]

thanks a lot!