Not sure what your client is, or what add-on you have or not but Copy and Paste works just fine. 

Adblocker? Scriptblocker? 

I copied from MS word also MS works but paste opp did not show when right clicking on intended forum page

I know this isn't DIRECTLY related, but I can tell you that ClipboardFusion is the best Clipboard management tool I have come across. We LOVE it.

Works fine for me in all my browsers following your workflow.  Are you using the quick reply editor or the full editor? And what plugins are active in your browser?

Use the keyboard shortcuts Ctrl + C, then Ctrl + V

Works for me when the option doesn't show up on a right mouse click. 

I'm using Firefox on Linux. 

If I right click in the quick reply dialog text area where there is no text, I get the standard web page "save page as... view page source" rather than text editing

If I type some text and then "right click" I get the "Undo, Cut, Copy, Paste... menu"

So to the OP:  Type some text into the box, select it and then right click your mouse.

Or use keyboard command CTRL+V or SHIFT+Insert to paste

Thanks I just tried the keyboard short cuts and they worked fine thanks to you all

scuwp: Use the keyboard shortcuts Ctrl + C, then Ctrl + V ...

Stick with the 'Ctrl +' key combo.

Don't do the very old school Shift + Insert/Delete. They don't mix.

scuwp:

Use the keyboard shortcuts Ctrl + C, then Ctrl + V

Works for me when the option doesn't show up on a right mouse click. 

IcI:

 

scuwp: Use the keyboard shortcuts Ctrl + C, then Ctrl + V ...

 

Stick with the 'Ctrl +' key combo.

 

Don't do the very old school Shift + Insert/Delete. They don't mix.