Yes!  Of course...  It is quite common for business analysts to be involved in the development of training materials such as manuals, instructional videos, how to guides, FAQs, etc.

As the bridge between system and technology, the business analyst is best positioned to understand how the system was designed to be used given that it was designed with the end users in mind.

Of course, do not understimate the system's users to come up with new ways to use the system which were not prevoiusly anticipated.