The basics of writing for an architect are generally similar to those of professional writers. Clarity and simplicity are essential as well as good structure and correct grammar and spelling. Further, writing should be specifically tailored to the reading audience. E.g. information prepared for business stakeholders typically requires less detail than information for engineers. Having a good foundation in writing is important, since information can easily be lost or ignored if it is not articulated well. Any written document reflects on the credibility of its author. It is therefore in the best interest of the architect to be proficient in this capability.
Especially relevant to the IT architect profession is the ability to describe information correctly and accurately. It starts with precise wording, but also includes proper use of terminology. Using standard technology and business terminology will ensure that all readers have the same understanding of the described content. The goal is to avoid ambiguity as much as possible, since it can lead to misunderstandings that can take a long time to resolve or even cause poor decision making. Language used in a document or email is often repeated in follow-up communication, so it is always best to pay attention to accurate wording from the beginning.
The most common use of written text is for the description of systems, specifications or other architectural artifacts. E.g. it is very common for an architect to write a document that outlines a new system in form of requirements, components, business rules or other artifacts. While diagrams are often the core of the document, it is the text that provides the framework and walks the reader through the different views to create a holistic picture of the system. There are many common practices on what formats to use for documents and specifications. Most mature organizations have guidelines and templates that are expected to be followed in order to standardize processes and representation of information.
Another common area of writing by architects is correspondence via email or communication portals. The purpose of the correspondence is usually related to gathering or distribution of information, but can also be more general in nature. E.g. it is common in practice to address critical follow-up questions to a meeting or document review by email. To be successful, it is important to be familiar with business correspondence practices, such as greeting and thanking the recipient. There are many casual correspondence practices that are being frowned upon in a professional environment, such as the use of smileys, slang, etc. It is best to avoid these completely, since they can result in reluctance to cooperate by the other party.
On a more senior level, an architect may be asked to write a report or paper about a new technology or the feasibility of an architecture proposal. An additional skill is required for this type of writing task, which is the ability to advocate an opinion and convince the user of a perspective or proposal.
There are many other areas where writing skills are important. E.g. architects may be needed to help with critical parts of product documentation or they can be authors of papers or blogs.