Like any craft, developmental editing is aided, and sometimes limited, by the tools of its trade. As a freelance developmental editor, I use Google Docs, the MS Office Suite, and Adobe InDesign.
Although Docs is popular with my clients because of its promised collaborative potential, but its tools aren’t well suited to projects with a long timeline, or (to be honest) multiple readers. MS Word can also be maddening: Its nonembedded fonts, nonuniversal autoformatting features, and processing limitations on long docs with tracked changes can pose annoying obstacles to efficiency.
But Word is still more navigable than Google Docs, as I’ve written about before, and it capably handles long dialogic projects.
InDesign offers another programmatic tool, but it typically applies to typeset projects, or projects already subjected to interior layout design. It is seldom flexible or navigable enough for early-stage work, so while I work in InDesign, designers and proofreaders work there more frequently and efficiently.
Excel, on the other hand, is crucial for tracking word counts and other project details, and for informing client content-management platforms. I augment it with a trusty shareable, interactive calendar (Google or otherwise), and a synced cloud-based folder.
Developmental editors, freelance and otherwise, are like project managers. Both plan, facilitate, and manage execution, and both simultaneously attend to micro, macro, and meta perspectives. The right (or right-enough) tools make such attention possible.