A business license is required when advertising a business. However, self-published authors aren't required to provide a business license.
The following Ads and images are prohibited:
<Pornographic or sexually explicit images
<Contain frontal and back nudity
<Feature graphic violence
<Include disturbing or disgusting images
<Violate copyright laws
<Contain hate speech, including verbal attacks based on gender, sexual orientation, race,
ethnicity, religion, disability, or nationality
<Reveal other users' personal information
<Advertisements may not be misleading and must be verifiable.
<Advertisements should clearly identify the advertiser and the product or service being offered.