Hi Rollin,
Let me try to understand the request here. In Office Online , “View only” is set by default when we open a document. This is a default setting with no option for changes.
To make the file editable, there are two options we can do to achieve this:
1. Open a Excel document> Find Edit WorkBook on the ribbon> Choose either Edit in Excel or Edit in Excel Online.
2. Go to a library where you’ve stored the document, edit the file in browser as below.
If I’ve misunderstood your situation, please provide more detailed information about your scenario. A screenshot or the details about where you have encountered this problem will be useful.
Thanks,
Jerry