To copy touch and hold on a word until a dialog box appears then choose the appropriate option such as Select or Select All. The word(s) are then highlighted, so now you can drag the sides of the highlighting to ensure you select all the words you want highlighted. Now touch and hold on the highlighted text until a dialog box appears and choose Copy.

To paste touch and hold where you want to paste the text until a dialog box appears and choose Paste.

This is pretty standard with touchscreen interfaces like iOS and Android. It probably works it bit better in iOS, but it works okay in Android too.