It is a confusing process. But yes, filing in court and serving your spouse are 2 completely different things. We can file a divorce COMPLAINT and never tell your spouse. But the “deadline” for him/her to react to our filing gets “pushed out” to the 35th day after we “serve” him/her.
Service is a term of art in the law. Normally if you hand someone a piece of paper, you can assume she/he has the paper. But in the law we don’t believe you gave it to her/him unless she/he signs another magic paper (called an ACKNOWLEDGMENT OF SERVICE) with a Notary saying she/he got the COMPLAINT, or we have a disinterested stranger who we pay to give it to her/him and then sign the magic paper with a Notary (that person is usually called a PROCESS SERVER).
It’s magical! Unfortunately, neither you (as the opposing spouse) nor your lawyer are allowed to sign the magic paper, because we may have incentive to lie! Nothing personal—in the law we assume everybody is lying.
Oh—I almost forgot—if your spouse hires a lawyer, that lawyer can also sign the magic paper. But that lawyer doesn’t need a NOTARY because, crazily enough, we trust lawyers! That lawyer can also file an ANSWER or an APPEARANCE instead of the magic paper.
So, in plain English, if we hand your spouse the filed divorce, without that magic, Notarized paper, we can’t prove she/he got it.
Once we have get the signed and Notarized magic paper, we send it to the court—and then your spouse has 35 days to hire an attorney to file an ANSWER.