Use easy words when you write. Complicated vocabulary is harder to understand.
Of course, write specialised terms if your readers are familiar with them but use everyday language when possible, particularly if the audience is not well-versed in technical terms.
Choose “begin” instead of “commence”, “buy” instead of “procure” and “use” in place of “utilise”. This enhances readability.
If in doubt, opt for the shortest word! Your text will be read faster and understood better!