Purpose is the “goal” of your writing, in other words its what you want your writing to achieve. The purpose of technical writing can be as simple as only being to inform or summarize a study (for example a lab report) or something far more in-depth such as persuading a government individual to grant you funding for a project. Purpose was one of the rhetorical elements that came first in the drafting process because the process often started with identifying a problem or topic, with that purpose and audience followed. The reason audience and purpose are always kept in mind at all times is that they are dependent on one another.
An example of a persuasive purpose would be the engineering proposal where my team and I addressed 3 mayors in Bay County and requested they help fund our storm shelters. We had to adjust our content accordingly to ensure that our writing will be effective in achieving its purpose. (Figure 16)