RegWriteMultiStringValue

function RegWriteMultiStringValue(const RootKey: Integer; const SubKeyName, ValueName, Data: String): Boolean;

Writes the specified REG_MULTI_SZ-type registry value. Returns True if successful, False otherwise.

In a REG_MULTI_SZ-type value, each string is separated by a null character (#0).

begin
  RegWriteMultiStringValue(HKEY_CURRENT_USER, 'Software\My Company\My Program',
    'MultiStringTest', 'String1' + #0 + 'String2' + #0 + 'String3');
end;