What are the differences between ad copywriting and copywriting?

Ad copywriting is the process of writing content for an advertisement. It is usually more concise and direct than other forms of copywriting. Ad copywriting aims to create a message that will persuade people to act, such as buying a product. It is designed to be persuasive and compelling and should be concise and powerful. 

Copywriting is the process of creating written content for a variety of purposes. It is more expensive than ad copywriting and often covers many topics. Copywriting can include writing content for websites, brochures, press releases, articles, and other marketing materials. The goal of copywriting is to create engaging content that is informative and persuasive, and it should be written engaging and compellingly while conveying the desired message.