I’ve been working on a project and we needed to add a custom submission form to a Tumblr blog. If you’ve never tried it, it can be a bit of a hassle. Tumblr’s official submission form is in an iframe so you can’t edit the fields or the styles. You can’t use your own server-side scripts.
So after slogging around for a while I came across Dropbox Forms on JotForm and oh my god it’s kind of the greatest. You can embed any kind of form, anywhere on your blog, and it’s easy. Maybe this has been around for a while and I’m just finding out but it’s not the first hit when you Google adding forms to Tumblr and it really should be.