Often times it's necessary for a client to update all of their email template from addresses. This is very common when installing Blesta at a subdomain for example. If Blesta is installed at sub.domain.com, emails will be from sales@sub.domain.com and billing@sub.domain.com. A user might also move Blesta and need to update the addresses.

Open to a better suggestion, but I propose that under Settings > Company > Emails where the email templates are listed, we include EITHER a window decoration "fas fa-cog fa-fw" icon like the Billing at a Glance widget, OR a button in the upper right that says "Bulk Edit".

On the resulting page, load a list of unique from addresses across all templates. For example, if we have billing@domain.com and sales@domain.com and only those used throughout all the templates then we would list those 2 on the left and to the right we would show an input box for the new address. If the field is blank, ignore/skip it. On submit, check that the email address is valid via regex or existing email validation function.

Then, update the from address for all matching emails to the new.

Requested here https://requests.blesta.com/topic/option-to-mass-change-from-email-for-system-emails