I don't know if this is exactly what you are wanting but just copy and paste is done normally by;

In email just hold the shift key ( Up Arrow looking button ) and highlighting the desired text then hitting CTRL + C to copy.

Open your config file via leafpad if you want ( leafpad /etc/conky/conky.conf ) or any other way and hit CTRL + P to paste.

Maybe I am not understanding completely what you want.