I was able to successfully copy and paste (command + c and command + v) from textedit to the terminal session. I was also able to successfully copy and paste from the browser to the terminal to enter the given credentials.
I have also successfully copy pasta using our new instant terminals and using our original cloud servers.
I am running MacOS Mojave version 10.14
I hope this helps.
Also, if you're interested, you can install iterm2 and customize your terminal a lot more. https://iterm2.com/
It sounds like you are working inside a lab environment, which is slightly different for copy / paste than inside our Playground servers and instant terminals.
I suspect that you will need to use the Shift + Control + Option(Alt) to open up the clipbard side window. Then Shift + Control + Option again to close it. After that, I think standard Control + V should paste the content that you added to the clipboard.
We realize this is (more) than a bit of a hassle, and we hope to have a better solution in place.
I hope this helps!
Are you using a learning activity/challenge? If so, the web based terminal for those currently does not support copy/paste.
If you're using a cloud server/playground server, then copy/paste should work, but as others have said the keyboard command may be slightly different.