If your vault is stored on a cloud service, such as OneDrive, you can use IFTTT to add notes by email.
How it works. You send an email to [email protected] and IFTTT creates a file in the desired directory. You can use the subject as the title and the message content as the body of the note. In addition, IFTTT can insert a link to download a single attachment.
I tested this with OneDrive, but it should work with Dropbox and Google Drive as well.
What are the limitations:
A letter can only be sent from the same address. Solved by multiple registrations in IFTTT.
You can only use one attachment. I haven’t figured that out yet.
Sometimes it can take a long time to work. This is solved using Zapper, but it is more expensive.
Create a dedicated outlook.com email address
Have your fault in eg dropbox
Make a zapier: when outlook email → adjust body to markdown → save in Dropbox folder with .md
I have it saved under by inbox folder in my fault.
Works fine for each email I send to my “dedicated” outlook.com email address.
It’s not ideal, but it works and it’s free.