Hello @Scott Wylie !
Welcome to Microsoft QnA!
I see youwant to Automate sending a Sheet to an Email address
A tool that is easy and already integrated into O365 in general is Power Automate
By using Power Automate, you can automate the process of sending Excel files from SharePoint to a predetermined email address. Although it doesn't involve adding a button directly within the Excel file,Power Automate allows you to achieve the desired functionality.
Here are some links with the Documentation
A trigger would be the change into the file and an action would send the Email
Another way is to add the Hyperlink feature on Excel , but the Mail Client will open so the user must enter manually the recipient.
Of course Excel can support VBA Scripts but it is a rather old school solution and doe not offer the agility of Power Automate !
In case you need more details , kindly post your feedback and we can work on this.
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!