That’s the reason we have to still use fax machines right?
I know there are ways to do encryption like PGP on your message directly or I think email sent over TLS? But that isn’t the default right and that’s why I can’t send a picture of my license to the insurance company directly over email?
Protonmail (which offers free accounts) lets you click on a padlock icon to this. You set an encryption password and a password hint for the recipient, and can then send a pgp-encrypted email. The message does not require a protonmail account as it directs the recipient to a web page where they enter the password. They can reply to you from that page with a message that is also itself encrypted.
It’s not quite what you’re asking but it will get your ID securely to your insurance company. I haven’t found anyone yet whose employer has blocked this ability.