Need Some Clarification About SEO Terms

Hello SEO Experts, please give me some clarification from your point of view for the below SEO-related question.

• Types of Meta Tags and Its Uses
• What is Canonical URL and its uses?
• Use of Alt tag in SEO
• Whats is the Difference between Title and Meta Title?
• What is the Current SEO Title Length and Why is Truncate in SERP?
• What are Crawling and Indexing?
• Uses of Sitemap and Without a sitemap, our web URLs are index(Reason)?
• Where we use the No-index tag and why?
• What is the File/Folder name for SEO?
  

Thanks.