Below are all the steps you have to do.
1)
EXEC sp_changepublication
@publication = 'PublicationName',
@property = N'allow_anonymous',
@value = 'false'
GO
EXEC sp_changepublication
@publication = 'PublicationName',
@property = N'immediate_sync',
@value = 'false'
GO
2) Add table to publication :-
exec dbo.sp_addarticle 'PublicationName' ,@article='TableNeedsToBeAdded',@source_table=' TableNeedsToBeAdded',@destination_table='TableNeedsToBeAdded',
@force_invalidate_snapshot=1
Go
3) Refresh the subscription : -
exec dbo.sp_refreshsubscriptions 'PublicationName'
go
4) Now run the snapshot agent which will only update the object changed/ added new object
exec msdb.dbo.sp_start_job @job_name='JobName'
go