Below are steps I undergone to register as self-employed individual status on BIR.
Note: According to BIR Personnel unless we do this registration we can't file ITR.

Step 1: Go to nearest BIR office to see if your account type is professional already. They will let you know which branch you will go to change your status.

Step 2: Once you arrive on your designated branch
Ask guard for 1901 form then ask number for officer of the day. Officer will verify that form and instruct you to go to Registration Concerns Department. I attached sample image below of form 1901 for reference.

Step 3: After that ask guard for form 0605 and 1906. Then get number for Registration Concerns Department. I attached sample image below of form 0605 and 1906 for reference.

Step 4: Ask if officer know someone that printing O.R. Believe me it is much easier that way because their referral already have all the documents required by BIR for a printing company. I attached sample image below of some documents that BIR will require from printing for reference.

Step 5: Make sure you have 4 copies of 0605 before going to any accredited bank of BIR. And pay the registration fee of Php500.00

Step 6: Photocopy the bank receipt. And Buy 2 columnar it is base on what the officer required you to buy. Then go back again to previous officer that ask you to pay the registration fee.

Final Step: Pass all documents for final verification then Officer will check the requirement list and encode your business. And will ask you to go back after 3 business days. I attached sample image of checklist for reference.