Just to add on to Scott's comment, SAP provides standard screen and country specific screen for infotypes. Typically, 2000 is the standard screen and 20nn is the country specific screen where nn = country grouping (10 = US, 40 = India etc.) You can find the country groupings from T500L.
Country specific screens are provided for certain infotypes because different countries may have different data points that need to be captured on an employee record. Infotype 0002, 0006 are good examples. It also allows SAP to build country specific screen logic in the underlying program MPnnnn00 where nn = infotype number (MP000200, MP000600 etc.)
Both standard screen and country specific screen can be further customized according to business requirements. Customization is for the fields on the screen and you can hide, make them mandatory/optional and so on. Since country specific screens are for a country, customizations is typically applicable for only that country. For some standard screens (infotype 0000, 0001), you can customize for a country. For example - if business area on infotype 0001 is not used in Brazil, you can hide that field from infotype 0001 just for Brazil. There won't be a Brazil specific infotype 0001 screen for this.
The two important configuration activities are:
SPRO > Personnel Management > Personnel Administration > Customizing User Interfaces > Change Screen Modifications (table T588M)
and feature Pnnn where nnn = infotype number (P0002, P0006 etc.)
SAP reads employee's country grouping and accordingly presents the screen as per the configuration. I suggest you go through the table and feature to understand configuration done in your system.
Hope this helps.
Donnie
