How to access dynamic array on a different form?

Question

I am trying to develop a small APP for my work, but I am having trouble finding information on the best way to pass a multidimensional array between forms.

Basically, I loop through an Excel file in form2 and put it to string array[worksheet.rows.count,12] (there are always 12 columns but unknown number of rows). Now, how can I access this array from form1? I know there is more than one way, which is primarily the reason I am having problems trying to find an answer by searching. Also, since the array is also 2000 lines+ and I am doing thousands of calculations within form1, not sure if one way would be faster than another.