InDesign is an exceedingly powerful, flexible layout, design, and publishing tool. InDesign is the print industry standard world wide. It is not for the casual user; one is not likely to "pick up and run with it" without a good head for software and computers, but should be able to use its basic functions.
With a couple of good training books, videos, or courses (and the time to go through the exercises), one could learn to use this software well and create almost anything -- print wise, from a tiny ad to a magazine layout, to large banners, to trade show booth art.*
With use, ID can become quite speedy to use too, and works smoothly with the rest of the Creative Suite, including dragging and dropping images files, pulling out Snippets to reuse, etc. One could import a Word document and map the styles so that it pulls in largely pre-formatted and flows into the layout nearly ready to go, but these are among more advanced features. Though not its primary function, some web files can be exported as well, to create web banners and ads. (Be sure your system is adequate.)
Is InDesign perfect? Probably not. But after using it for many years, I have to say that I feel it is darn good; there are few others in its league or as widely accepted in the industry today.
(*What are my qualifications to comment like this? I'm a professional graphic designer who worked in the printing industry for 15 years prior to my current 15 year stent as an in-house graphic designer; I work for corporate marketing and communication for an international company with over 250,000 employees. I've used this product since, well, before it was this product -- beginning with Aldus Pagemaker that later evolved into InDesign. It is a good product.)