Note: This feature comes with Grammarly Premium.
To change your domain/document type in the online Grammarly Editor or the native (desktop) app, click Start Assistant (or Correct with Assistant) in the upper right corner, then select Goals > Domain:
You can also get customized suggestions by selecting the Intent, Audience, Style, and Emotion of your text.
If you're using Grammarly for Microsoft Office, you can change your document type by clicking General in the Grammarly toolbar and selecting your preferred one:
For more information about document types in Grammarly for Microsoft Office, please check this article.