How to do LLP registration of a already existing partnership firm?

A firm may apply to convert into a limited liability partnership if and only if the partners of the LLP into which the firm is converted comprise of all the partners of the firm and no one else.

A firm may apply to convert into a LLP by filing with the registrar the following documents :

1. A statement by all of its partners in such form and manner and accompanied by such fee as the 

Central Government may prescribe containing following particulars:
 a. the name and registration number of the firm (if applicable); and
 b. the date on which the firm was registered under the Indian Partnership Act

2. Incorporation document. It shall contain the following details:
 a. Be in a form as may be prescribed
 b. state the name of the LLP
 c. state the propsed business of the LLP
 d. state the address of the registered office of the LLP
 e. state the name and address of each of the person who are to be the patners of the LLP on incorporation.
 f. state the name and address of the persons who are to be designated partners of the LLP on incorporation.
 g. contain such other information concerning the proposed LLP as may be prescribed. 

There after on receiving the documents, the registrar shall, as per the section of the LLP Act, register the documents and issue a certificate of registration.