You should create an Excel survey so that nobody knows who else is filling out the form and they can't edit anyone else's responses.
- Go to OneDrive
- Select New > Excel survey
- You will then go through a wizard asking you to create questions.
If you want to make people answer all of them then mark each question as Required.
- Add as many questions necessary
- Click Share survey
Copy the survey link that is generated
Share the link to how every many people you want to answer the questions
They will not need an account and can answer the questions anonymously.
But they are able to answer the survey again by reloading the page, so you may end up with people filling out the form more than once.
The spreadsheet will appear with the rest of those under your account.
If you ever want to edit the questions you can by:
Insert > Survey > Edit Survey