How is the best way to work with step by step documentation to software maintenance

I'm working on a web project in java and I have a problem with the documentation we are making.

The goal is to has step by step how to do some basic stuff for system maintenance, like add fields to a report, for guidance for me and another programmer and maintain consistent code.

For this I have multiple Word documents with screenshots and step by step how to do things in the project code, also we comment the code but not step by step.

The development IDE we use is Intellij IDEA Ultimate.

The problem we have is that the Word are not comfortable, because it has many pages with a large index (about 175) and has a huge time-keeping when we make a change. For example: we are now changing the version of the IDE and we take more or less a couple of hours of extra work to change and adapt the word files.

We have also tested using Wikis (like tikiwiki), but it was difficult to maintain with images and we dont feel very comfortable using it.

1- how we could manage this documentation better to fulfilling my goal?, there is a better way to do it? 2- Is there a practical way to integrate the IDE?

Greetings