Technical Writing: Manuals.
Technical writing bridges technology to the people that use it. The function of a techical writer is to, clearly and economically, let users understand how a piece of technology works and how to use it to suit their purposes. It's not exaggerating to say technical writing enables businesses to let customers effectively use their products, and to let employees effectively do their job.
Technology today is complex. Even common household items like telephones and dishwashers require programming guidance and some technical sense of their inner workings -and often include a multi-page manual.
I've worked for large corporations and businesses in the aerospace, electronics and software sectors as a technical writer. Those jobs all involved the writing of many large and complex manuals and related documents of a highly technical nature. I've produced detailed manuals for businesses and organizations in other fields also.
My technical education (I have an Engineering Degree) and experience allows me to understand technical concepts readily. My writing background allows me to explain them clearly and accurately whatever their complexity.
As well, I can edit or revise documents written by others for style, clarity and technical accuracy and consistency.