Just try it out yourself

Do some searches at the iStock site. I did this recently, and at the left hand side, there are options to show only Creative, only Editorial or both (see attached screenshot).

iStock has a very good article on this topic:
https://contributors.gettyimages.com/article.aspx?article_id=4837

The article has many helpful examples and also a section on what they call "Illustrative Editorial", where you try to portray a concept.

As opposed to Getty editorial, iStock does not take "cutting edge" or newsworthy editorial content. You need to think "timeless editorial", in the sense of "a typical day at the busiest shopping street in city XXX". Things used by newspapers, magazines and travel sites.

I've been contemplating iStock editorial myself, recently, and am trying to figure out how to choose between editorial and creative.
It's not a simple as "submit as editorial if you can't get a model release", as I used to think

Also, the image still has to be of good technical quality, though of course the bar has moved pretty low over the last years for all microstock agencies...
The time where we were spending our time fixing chromatic aberration at the pixel level is definitely a thing of the past.

Doing searches at the iStock site for editorial and some topics and concepts you're interested in, is an interesting way to learn, and that's what I'll be doing myself.

Good luck