You cannot directly embed a donation form in an email. However, you can use our Donate button.
From your dashboard, click on the Campaigns link at the side menu. Choose the campaign you want to add to your email. In the same container, click the Embed Code button with the code (</>) icon. Then go to the Donate Button tab.
From there you can grab the code that is usable for your email campaign. If you have your own button images, you can link it to your https://donorbox.org/campaign page.