Form POS-015 at a glance
What it is: Form POS-015 is the NOTICE AND ACKNOWLEDGMENT OF RECEIPT-CIVIL.
Where and when to file: Return this form within 20 days from the date of mailing shown in Date of mailing. Your failure to complete this form and return it within 20 days from the date of mailing shown in Date of mailing may subject you (or the party on whose behalf you are being served) to liability for the payment of any expenses incurred in serving a summons on you in any other manner permitted by law. The summons and other documents identified are being served pursuant to section 415.30 of the California Code of Civil Procedure.
A filled-in Form POS-015 example: a defendant returns the signed form

How to fill out Form POS-015, box by box
Attorney or party without attorney
Superior Court of California, County of, and the case
To, Date of mailing and the sender
This acknowledges receipt of: a copy and Other (specify)
To be completed by recipient and signing

To be completed by recipient: enter the Date this form is signed, then (TYPE OR PRINT YOUR NAME AND NAME OF ENTITY, IF ANY, ON WHOSE BEHALF THIS FORM IS SIGNED) and sign (SIGNATURE OF PERSON ACKNOWLEDGING RECEIPT, WITH TITLE IF ACKNOWLEDGMENT IS MADE ON BEHALF OF ANOTHER PERSON OR ENTITY).
If you are being served on behalf of a corporation, an unincorporated association (including a partnership), or other entity, this form must be signed by you in the name of such entity or by a person authorized to receive service of process on behalf of such entity. In all other cases, this form must be signed by you personally or by a person authorized by you to acknowledge receipt of summons. If you return this form to the sender, service of a summons is deemed complete on the day you sign the acknowledgment of receipt.
Sources
[1] Form POS-015 (Rev. January 1, 2005), Notice and Acknowledgment of Receipt-Civil, Judicial Council of California (the Official source link on this page).




