If the substance is illegal/unlawful in the US, it is against the law to import it or order it from overseas.
(in the US) It is not against the law.
No
yes
UPS international as well as FDL is are two of the popular companies that you can mail your packages overseas. You can also use USPS where you can mail packages, however they may not mail certain items overseas,.
You use an air mail stamp.
Surface mail is overseas mail that goes by ship rather than by air. Parcel mail is for parcels.
you must write clearly the name and address including a postcode of the person you are sending mail to. It is optional to write on the back of mail your own name and address unles sending mail by registered or overseas. If sending mail overseas you must also write the country.
No
No, it is not legal to open mail that is addressed to your house if it is not intended for you.
Most overseas mail is now by air.
It is not legal to send poop in the mail as it is considered a biohazard and can pose health risks. Sending poop through the mail can also violate postal regulations and lead to legal consequences.