why can I send the answer to the teacher

Ask your teacher. It's possible that your teacher has entered your name already and that's why you don't need to type it again.

Hello everyone!
To help you to investigate please provide me with more details, please provide me with the URL and title of the worksheet, or workbook. That way I can test it on my end, please contact us at [email protected], we'll be glad to help you out.
Cheers.