As others have already mentioned, sys.tables will show the time the structure of the table was last changed. And you will need a trigger to show when the data was last changed.

So, here's an example:

--make a couple of test tables

if exists (select 1 from sys.tables where name = 'DataMod') drop table dbo.DataMod

go

if exists (select 1 from sys.tables where name = 'DataTest') drop table dbo.DataTest

GO

create table dbo.DataMod([schema] sysname, name sysname, modify_date datetime)

go

create table dbo.DataTest(TestCol1 int identity)

go

-- build a trigger to store off whenever the data is changed on the table

CREATE TRIGGER [trg_data_test] ON dbo.DataTest for update, insert, delete AS

insert into dbo.DataMod select 'dbo','DataTest', GetDate()

GO

-- show when the table was created and modified

select name, create_date, modify_date from sys.tables where object_id = object_id('dbo.DataTest')

GO

-- add three records

insert into dbo.DataTest DEFAULT VALUES

GO 3

-- add a new column to the table

alter table dbo.DataTest add TestCol2 uniqueidentifier default newid()

GO

-- show that the table was modified

select name, create_date, modify_date from sys.tables where object_id = object_id('dbo.DataTest')

GO

-- add three more records

insert into dbo.DataTest DEFAULT VALUES

GO 3

-- show that the data was added, and that the table that stores when the table was last modified has been added

select * from dbo.DataTest

select * from dbo.DataMod

GO