hi krishna,
Choose References > Table of Contents.
Choose one of the following items on the menu.
There may be custom tables of contents on your menu. If you click the thumbnail for a custom table of contents, your table of contents will be inserted into a content control. (There is further information about content controls below.)
There are two built-in 'automatic' tables of contents: Automatic Table 1 and Automatic Table 2. If you click the thumbnail for either of these, your table of contents will be inserted into a content control, and Word will add a heading. (There is further information about content controls below.) The only difference between the two is the text of the heading ("Contents" and "Table of contents").
There is a built-in "Manual Table". This takes you back to the era of the electric typewriter. If you like typing things out for no good reason and your life expectancy is a lot longer than mine, this is for you.
At the bottom of the menu, you can choose Insert table of contents. This displays the Table of Contents dialog that was also in earlier versions of Word. If you want two or more tables of contents in one document, you must choose this option for the at least the second and subsequent tables of contents.