Connecting to wordpress database in my application [closed]

What you likely need is the function wp_insert_post(). In your backend (not the WordPress backend, just so we’re clear), you’ll need to do a minimal load of WordPress to allow wp_insert_post() to work. You can do this by define( 'SHORTINT', true ).

Some additional reading on doing a minimal load of WordPress:

In these questions you will also find information how to do this asynchronously, should you desire to do it that way.