I've been a loyal user of Mailparser for years. They provide an email address where you can send any email (tracking, invoice, etc..) and it extracts data based on pre-defined rules.

Then, you use Zapier to do almost anything with that data: send it to a google sheet, use that info to trigger an email to your customer, etc... The possibilities are endless.

My favorite use case was to use it for tracking emails sent out to our customers. We would have fedex-generated emails from our 3PL sent to a @mailparser address, which strips relevant info from the email, sends it to our Sendgrid account, re-skins the email in our format and sends it along to the customer as us. Won't bore you with the details, but we had a unique challenge that required something like this.