Launching and email account from an email address embedded in an Excel Spreadsheet

I have an Excel spreadsheet containing a lot of customer data, one element of which is their email address (they have opted in under GDPR rules).  When I click on their email address, an email is launched but it does so using an email account I no longer use.  I cannot see where I enter the default email account I wish to use when launching via a link in the spreadsheet.  It is probably very simple, but I cannot find where to amend the address, so can anyone help please?

Thanks and regards

Peter