Are Technical Writing and Instructional Designing the Same?

Although I don’t regard technical writing and instructional designing different, I do acknowledge that the tools and methodologies both use are quite different.

Writing tools are of critical importance

Which is the best and the most reliable technical content writing software for any technical content writer?

There isn’t one tool that I’d pinpoint as the best of all. But based on your organization’s standard processes, requirements, budget, delivery formats, and time at hand, you can still zero in on what software you require for your organization.