Hello Rehana Malik,
Type of SEO need to be cleared. I mean type of SEO are on-page and off-page and there are many techniques involved in both the types. So please elaborate your question so that help can be provided in perfect manner.
Heading tags are used to define heading of the webpage and they are in between h1 to h6 among which h1 tag is most important and least important is the h6 tag.
You can make use of tools that are useful and can help you to get better results which are as follows:
Google Webmaster
Google Analytics
Google Keyword Planner
smallseotools
On page can be defined a process in which websites itself helps to improve the position in search engine which involves meta keyword, title and description optimization while in Off page creating backlink to the site to improve the ranking in the search engine is involved.