To Get all columns information of a table we can use following command
GO
SELECT st.name, sc.name,sc.is_identity AS IdentityColumn,
sc.is_nullable AS NullableColumn,
sc.max_length as colmaxlength,
sty.name as columnType
FROM sys.columns sc
INNER JOIN sys.tables st ON st.object_id = sc.object_id
INNER JOIN systypes sty on sty.xtype = sc.system_type_id
ORDER By st.name,sc.name
GO
Or we can use following statement
SELECT TABLE_NAME,COLUMN_NAME,DATA_TYPE,
CHARACTER_MAXIMUM_LENGTH,
IS_NULLABLE
FROM [INFORMATION_SCHEMA].[COLUMNS]
Enjoy 
!!!
