WeGive maps only to standard Salesforce State and Country picklists, which are the standard codes used across all Salesforce instances. These are two-letter ISO codes.
Here are some examples of these Standard Country Codes:
United States: US
Canada: CA
United Kingdom: GB
Australia: AU
India: IN
Germany: DE
Here are some examples for the United States State Codes:
Alabama: AL
Alaska: AK
Arizona: AZ
Arkansas: AR
California: CA
Colorado: CO
To learn more about implementing Standard Country and State codes in Salesforce, click here.
To learn more about Standard Countries in Salesforce, click here.