How to enable multiple selection in the Matrix table field?

I believe this is a duplicate thread as you have already opened a thread with the same concern. 

I-have-created-a-sign-up-form-using-a-matrix-I-have-five-columns-with-buttons-I-am-not-able-to-press-more-than-one-button-How-do-I-fix-Also-how-do#0

Please refer to the original thread you have opened for this concern as one of my colleagues is already on it.

Thank you.