Google wants you to provide content that fits the needs of people and not those of algorithms. So if you write a high quality text for your target group, it will also improve your SEO ranking. For most SEO texts a length of round about 300 words is appropriate, because it is a good compromise - concise but long enough to provide the reader with a lot of interesting information. But this is just a rough recommendation. The most important thing is the content itself and its editing.
Those are some things you can do to optimize your texts for Google and for your readers. You don't have to take all these tips one-to-one, but it helps to keep them in mind if you want to write successful search engine optimized texts.