Speaking on behalf of all of us who labor in the Pilgrims Office at Santiago, at the end of your Camino, we do sincerely appreciate it when the blanks in the front of your credencial are all filled in appropriately. Providing your name,"home town," starting date and place, how you traveled (foot, bike, horse), and signing the front page, all help move the process along.
Personally, I obtain my credentials from American Pilgrims on Camino (APOC) -
http://www.americanpilgrims.org
Each year, this document comes to me partially filled out using a laser printer. My name, hometown and country are already completed. I finish the inside front page and away I go.
Your national pilgrims organization may also make credentials available to you. Or, you can order them from Ivar here in his store. The credentials he provides are the same credentials sold in the Pilgrim Office.
Also, should you lose your credential and it gets forwarded to the Pilgrim Office by whoever finds it, we can more easily return it to you when you arrive if you have filled in the front page. The process is simple. An arriving pilgrim comes to us stating that they lost their credencial at (place) on (date). We will ask the person to show us an identity document, then we rummage through the box(es) of turned-in credentials to try to find yours. If you are lucky and a good samaritan forwarded your credential to us, you are reconnected to your document...smiles all around... Of course, if you neglected to write your name in the Credencial, who is to say that is yours?
As an aside, if this happens (you lose your credential), try to obtain another credential along the way and pick up where the other document left off, obtaining sellos each day. If the first document gets to Santiago, we may be able to stitch together a complete record of your progress on Camino. Alternatively, get a piece of paper to collect your daily 'sellos' on to establish your "line of march."
All evidence is good evidence. But showing up empty-handed and with only a good story alone can result in disappointment.
When you do get to the Pilgrim Office, if you have all the appropriate blanks filled in ahead of time, it saves having to take the time at the Pilgrim Office counter to ask you to do it and delay processing for the others in the queue. Yes, it does not take long to ask this of one pilgrim, but if you take that extra minute or so and extrapolate out to a large percentage of folks in the queue, it clearly adds up to extra waiting times.
Queue management was my mien when I was working. It remains a skill I brought to the Pilgrim Office in 2014, 2015, and will again this summer.
I hope this helps.