It surprises me how many people don't use a clipboard manager. I use PasteBot on the Mac.
I use Pasteapp on macOS and FastKeys on Windows, which comes with other useful stuff, such as a shortcut for controlling volume by using the mouse scroll wheel on the right edge of the screen, macros, and a text-expander. The ones I use the most are:
ddate = 2020-02-18 ttime = 03:40:26 nnow = 2020-02-18 03:40:28 @@ = my email