If you are looking for the character count statistics in a whole worksheet, there are no direct ways to get.
You can view workbook statistics by clicking the Review> Proofing> Workbook Statistics. There you’ll find data on the end of the current sheet, cells with data, tables, pivot tables, and formulas for the current sheet. You can also find statistics for your workbook.
What can you do? One way is to click Ctrl + A to highlight all the data, copy it, and paste in Word. How to do character count in Word you can find in our posts:
The other way is to use a character counter, which can do a character count for you.