Google’s Danny Sullivan said on Twitter that Google’s algorithms cannot know that a particular expert has written your content. You should try to create expert content that sends the right quality signals.
Google’s John Mueller said earlier this year that it’s best if an expert has written your content.
I think the advice is misunderstood. People should aim for great content. Experts can help produce that. But we don't know a particular expert has written anything. However, if you have good expert content, that might produce the types of signals we find correspond with such.— Danny Sullivan (@dannysullivan) October 8, 2019
Further information on how to implement E-A-T can be found here.
Sending the right signals is important
Although Danny Sullivan does not go into the details of how the evaluate the quality of content, it is likely that it helps to have a professional web page structure. Web pages should be error-free.
The website audit tool in SEOprofiler checks your web pages for spelling mistakes, and it checks your website for other things that can have an impact on your Google rankings: