Yes it will help you to get better ranking as Google prefer those sites which have XML sitemap.

yes, you should add sitemap to your website, its helps to your website

yes sitemap is very important for a website ranking in Google

Yes it will help.
Consider it like this: would you manage to get faster on a new terain if you had a map? If yes ... this also answers your question.

Hving Sitemap is helpful and beneficial for the website because it is the place where the complete site available under one roof with the all internal links and resources.

Site map creation is one of the main on page SEO optimization techniques.As a result, the users will come to know overall pages containing in a website.It is one of the plus point for search engine rankings,considered by google.

Yes, you can place HTML & XMl sitemap on your website. HTML sitemap helps visitors to know your websites navigation & XML sitemap helps to search engine crawler to crawl your website

Yes add a sitemap to your site. This will give the serach engines chance to index all your pages very fast.

yes, absolutely. It is invaluable and helps the search engines index your site