delivery receipts = read receipts? They are a setting.
Tap on their name to change the "to" address; here it gives me a list of their Apple ID email and phone number to pick from.
You can enable fall-back for contacts which fail to send via iMessage to instead send via SMS, but I don't think you can send SMS to a phone number registered with iMessage by default without disabling iMessage globally.
Tap on their name to change the "to" address; here it gives me a list of their Apple ID email and phone number to pick from.
You can enable fall-back for contacts which fail to send via iMessage to instead send via SMS, but I don't think you can send SMS to a phone number registered with iMessage by default without disabling iMessage globally.