International freephone 800 numbers
Phone numbers for international freephone services 

allow free calls to a single number available in a given country (Freephone Number). In this case 800 is the area code. Companies using 0800 numbers cover the cost of calls, which allows customers to make free service calls.

enable free calls to a single number available in many countries (Universal International Freephone Number). +800 works as if it was a country code.

This is a way to establish a common hotline number to be printed on product packages distributed in many countries.