Is this for students to work on the problems in MATLAB Grader or on their own version of MATLAB?
You can add files to a MATLAB Grader problem. These files are added to the current folder of the problem, meaning they are available to the students to use in their solution.
Students can't see these files easily, so it is recommended you provide them the names of the files as well as instructions of what they are to do with the files in the problem description. If you would like to provide students access to the files to use outside of Grader, you can use the hyperlink to the file provided in Grader once a file has been added. Note that the name of each added file is a hyperlink. You can see an example of this in several of the Getting Started with MATLAB Grader example problems available in the Add Problem screen. Here is a screen shot of the "Determine the drag coefficient by fitting a polynomial to velocity-force data" problem.
Here, we opted to have the Learner Template load the data for the learner. However, you could also have the students do this themselves if you so desire (and they have been taught how to do it already).