Changing boolean value in template to a word

Changing boolean value in template to a word

I was wondering if there is a way to change the value of a boolean field to show a word such as 'yes' or 'no' when trying to export as an email/pdf. I see there is a way to manage and edit fields within zoho writer under mail merge.

Unfortunately there is no way to use mail merge for the Cases module so I'm using the email template builder on the CRM

Thanks