CELPIP writing task 1 is called Writing an Email. You are shown a short situation, usually four or five sentences of realistic Canadian context, and underneath it three bullet instructions that tell you exactly what your email has to contain. You then write that email, about 150 to 200 words, in roughly 27 minutes, typed into an on-screen editor. Task 1 comes first in the writing section, before Task 2, and both are marked by trained CELPIP raters rather than by a machine.
The part that catches people out is that Task 1 has two faces. The task itself never changes, but the reader does, and the reader decides your register. If the scenario points you at a customer relations department, a city councillor, a college registrar or a condo board, you are writing a formal email, which is what this page covers. If it points you at a cousin, a friend or a teammate, you are writing an informal email, and the rules of the game shift completely.
A formal email on CELPIP is not the stiff, archaic thing many candidates imagine. Raters are not looking for "I am writing to hereby inform your good self". They are looking for the register a competent adult uses when writing to an organisation that has something they need: clear, polite, specific, and organised so the reader can act on it. The best mental model is that you are writing to a real person who has forty other emails in their inbox and will act on yours only if it is easy to act on.
That is why the five samples on this page are all built around a request. A delayed suitcase, an uncleared sidewalk, a course deferral, a mistaken charge and a proposal to a condo board. In every case the email exists because the writer wants something to happen, and every sentence either establishes the facts, shows the impact, or names the action. Nothing is decoration. That is the shape of a high band Task 1 answer.