First, per 21 USC 801 and 21 CFR 300 (Controlled Substance Act and codification), only a licensed pharmacist or medical doctor may dispense a controlled substance. Second, per the United States Postal Service (USPS) 47 Controlled Substances and Drugs, only narcotics, hallucinogenics, stimulants, and depressants may be sent via USPS by the aforementioned licensed pharmacist/medical doctor to a patient. Third, codeine is an opioid, not a narcotic; and opioids cannot be sent through the USPS.
No, you must use US postage stamps.
The stamp has to be accepted where you mail the letter. If you are mailing in Canada, you need a Canadian stamp. If you are in the US mailing to Canada, you can use a US stamp.
Yes. All international mail is sent with the postage from the country of origin.
A person who delivers mail.
Yes
Yes, you can obtain codeine products with a prescription.
In the US, codeine is a schedule 2 drug that may be prescribed by a medical doctor to relieve pain, for the most part. It may also be used to relieve a severe cough. It can only be used by the person to whom the prescription applies. Selling codeine on the street or allowing others to take a person's prescribed codeine is illegal.
No, US post offices do not sell Canadian stamps. Canadian stamps are issued by Canada Post and can typically be purchased at Canadian post offices or through their official website. If you need to send mail to Canada, you can use US postage or go to a local retailer that sells international stamps.
Yes, if they get a marriage license.
Codeine Phosphate Linctus 15mg/5ml (cough medication, Codeine Linctus) or Codeine Phosphate 25mg/5ml (pain medication, syrup)
YES, although the denomination is different for US lettermail.
The US post office does not deliver mail to Iowa from Ohio