Hope you are looking for something like this:

DECLARE @LoginName VARCHAR(128);

DECLARE @dynsql VARCHAR(max);

DECLARE @default_db VARCHAR(200) = 'AP';

DECLARE @role_name VARCHAR(100) = 'PaymentEntry';

DECLARE c_login CURSOR FOR

SELECT LoginName

FROM NewLogins;

OPEN c_login;

FETCH NEXT FROM c_login INTO @LoginName

WHILE @@FETCH_STATUS = 0

BEGIN

SET @dynsql = 'CREATE LOGIN ' + @LoginName + ' WITH PASSWORD = ''' + SUBSTRING(@LoginName, 1, 4)+'9999' + ''', DEFAULT_DATABASE=' + @default_db;

EXEC (@dynsql);

EXEC sys.SP_ADDSRVROLEMEMBER

@loginame = @LoginName,

@rolename = @role_name

FETCH NEXT FROM c_login INTO @LoginName

END

CLOSE c_login;

DEALLOCATE c_login;