What is the best tool to create sitemap?

Depends on your needs. If you need to crawl large websites and create many different types of sitemaps, try A1 Sitemap Generator

I agree with @Webhelpforums!

Slickplan. An intuitive tool that will help you easily create elegant and professional-looking sitemaps.

Best Sitemap Generator Tools

Slickplan.
Dynomapper.
Writemaps.
Mindnode.
PowerMapper.

1. XML-Sitemaps.com
2. Screaming Frog XML Sitemap Generator
3. Inspyder Sitemap Creator
4. Flowmapp
5. GitMind
6. Slickplan
7. GlooMaps
8. Writemaps
9. Yoast SEO (plugin)
10. Google XML Sitemaps (plugin)

agreed with @Webhelpforums!