How to copy paste in firefox?

Firefox still cannot copy paste? I have always recommended Firefox to all my clients, however I may have to recommend another option soon since the ability to copy paste is important to most. In my case, I frequently have to copy paste to maintain websites. Now find myself using other browsers and may soon recommend other browsers to my clients as well. So many Firefox users agree this should be resolved. There must be a way of resolving this! == This happened == A few times a week == A while ago