You must not use free domains, because AdSense does not gives them approval, You can buy any domain from Godaddy or Namecheap or any other domain service provider.
and many other domain extensions.
You Can Get Approval from Google AdSense.
Follow These Few Rules And You Will Get Your Approval in a Few Days!
- You should have at least 25 Articles/Posts with 500 Words Each Article/Post.
- You must not copy past posts/articles from other websites into yours.
- You must write quality and unique content.
Important Pages To Implement on Your Website/Blog:
- You Must have the followings Pages on your website/blog [VERY IMPORTANT]
- Disclaimer Page
- Contact us
- About us
Once you fulfill these requirements, You can easily get your approval from AdSense.