To communicate a feeling, opinion, or fact clearly through words.
“I am writing to express my disappointment with the service I received.”
“I would like to express my appreciation for your quick response.”
In CELPIP Writing Task 1, 'express' is essential for complaint or feedback emails, as in 'I am writing to express my concern/dissatisfaction/appreciation.' It signals to the reader exactly what kind of message follows and helps you structure your opening sentence clearly.
Synonyms: convey, voice, communicate