The best ad copy length depends on where it's used, but short and clear usually works better. People often scroll fast, so your message should be understood in just a few seconds. A short ad, around one or two sentences, can attract attention if it's simple and focused on one main benefit. Longer ads can work when you're explaining something new or giving more detail about your product. The goal is to make every word count and avoid extra phrases. Test different lengths to see what gets more clicks or sales before deciding what fits your audience.