I am creating a custom content type named "Invoice". This content type is having attributes like Company Name (entity reference to company content type), Bill details, tax details and calculations. Can you please suggest how can I get elements/attributes like shown in an image in custom content type add new content form?
field_collection module allows you to add a field (Bill details) that contains a collection of fields (Amount, Service Tax, VAT, etc.). Set it to accept multiple values and you get a list like the one shown in the photo.
In your template you'd build a layout for your fields and output form fields in place like this
<?php print drupal_render($form['fieldname']);?>