I don't know why but from the title I was kinda expecting and even hoping for the opposite - that you'd type it up and it'd make a ye olde letter PDF/jpeg and attach it to the response :-)
If you ever wanted to type up a "handwritten" letter, there are some tools out there to create a custom font from your handwriting!
Interesting! Do you have a link or term to Google?
Sites like [calligraphr](https://www.calligraphr.com/en/) can help you create fonts from your handwriting. Also, here's an old project for creating something that looks handwritten on paper.
One thing more annoying that reading someone's horrible handwriting is having to install a custom font just to read an email. I honestly do not know whether the security setting on my work machine even allows for custom/bespoke fonts in email. It has never come up before.
Ah, I was envisioning that you'd turn the "letter" into a PDF. Maybe use a weathered parchment background for extra effect :P
I was envisioning an image or PDF (which lets you embed the font, effectively) but "click here to install my font" is somehow even funnier
Definitely want to try that too!! In general I think people sending an email expect a text format reply, but there's something sad about losing that handwritten letter :) Plus of course, drawings → attachments!