Hello Jennifer,
If you use Windows OS you can select text in a document for example and press CTRL+C to copy and Ctrl+V to paste to your template text object.
If you use Mac OS you can select text and press Command+C to copy text and Command+V to paste it. Where is a Command key it is a propeller ⌘ on your keyboard that is located under Z or X button.
Best regards,
Mathew Brown