acknowledgment of receipt

It's a carrier feature, some carriers support such, some don't. So, contact your carrier to see if they support such.

If you think you knew the answer then why are you posting here? You got an answer, move on.

If you think that Apple somehow controls this and you want the feature then go here:
http://www.apple.com/feedback/iphone.html

Or are you just wanting to rant/argue?

And it is a carrier dependent feature.

Do they have phones in France?

If yes, first call your provider and ask if they have this service. If yes, but it requires a prefix then use the link I provided and send your feedback to Apple.

Apple cannot add a feature to their OS that your provider does not support.

I've had no phones with this feature. Why? My carrier didn't offer itvso it wasn't an option on my phone.

Made that call yet?

Do this:

Create an Excel spreadsheet, copy all of your contacts to the spreadsheet, at the top of each column make it a date/time field, get an app from the app store that permits editing spreadsheets, install the app on your phone, copy the spreadsheet you created to your phone. Now, when you send an SMS, call the contact, ask if they got the SMS & to confirm the date/time, if yes, go to your spreadsheet & mark such next to the contact, if no, do the same, but keep calling until the contact confirms they received the SMS. Do this for every SMS...voila..you've got your own built in delivery confirmation report/record, no carrier intervention/participation required.

I've had no phones with this feature. Why?

Most likely because you live in the US, where SMS receipts are not common (possibly because I think many/most people have to pay to receive SMSs there, unlike the rest of the world).

In Europe, where the OP is, SMS receipts are a feature of (AFAIK) every network, and phones sold here have a menu option built-in to the phone, to turn them on and off without having to enter a code manually every time you send an SMS.

Even on a European network which provides SMS Receipts as standard, Apple have not provided a menu option in the OS to turn them on and off. That is what the OP is asking for.

Just curious, why do you want this?

Just have quoted the whole sentence Julian. It was a rhetorical question.

The point, which most people here seem to have missed, is that +even if+ your network provides SMS receipts as a feature, Apple have not provided the menu option in the OS to turn them on and off, as on other phones. In the iPhone's case, the rest of your sentence wasn't applicable.

Sorry, not in the mood to argue or clarify. You are right as to the point and the OP needs to send feedback.

Tell Apple:

http://www.apple.com/feedback/iphone.html