After processing your original data, you can use xlswrite() or dlmwrite() or csvwrite() to write the data to a file. For more flexible output, you need to use fopen(), fprintf(),fclose(). Check the help for sprintf() to find out the output format.
Simple example if you just want to output a regular numerical matrix.
xlswrite('test.xls', rand(3,4));
csvwrite('test.csv',rand(4,5);
