How To Add Pagination In WordPress Blog

1. Go to Settings>Reading from WP dashboard and then choose how many post to show on per page.
2. Add these line after end of while loop

<?php 
    endwhile;
    //previous_posts_link( );
    //next_posts_link( );
    echo paginate_links(  );
else: ?>

ANOTHER WAY(Plugin):

WP-Paginate is a simple and flexible pagination plugin which provides users with better navigation on your WordPress site.

WP-Paginate