In order to make a call to another country you're going to need this particular dialing code. There are numerous websites out there, including Blurtit, which will give you access to codes according to country and region. The codes are typically two or three digits long, obviously excluding the '00'. For China you need to dial 86 and for France you need to dial 33. It's pretty simple!
If you want to make a call from the US or Canada, however, you should use the exit code '011' and the country code, and then type in the phone number after that. All of the numbers combined will give you the number that you need to call to be connected to the foreign country. Countries that belong in NANPA, the North American Numbering Plan Area will be able to be dialed just as you would if it was a long distance call in the US. This means you type 1+the area code+ the phone number. Some areas that are included in this list are the US, Canada, Virgin Islands, American Samoa and Guam.