How to create a counter in Excel online (Excel 365)
Solution 1:
There are two possible ways for O365 on the web:
- Create a web add-in where you can develop a custom UI (it can be a task pane) with a counter, see Build an Excel task pane add-in.
- Use Office scripts, see https://docs.microsoft.com/en-us/office/dev/scripts/resources/vba-differences for more information.
I suppose web add-ins is the right choice for a custom UI (a task pane).