Try this
declare @no as varchar(50)
declare @TName as varchar(50)='tblOrder';
declare @CName as varchar(50)='OrdId';
declare @qry as nvarchar(500)
declare @count as int
set @qry='select @count = count(*) from '+@TName;
print (@qry)
exec sp_executesql @qry, N'@count int OUTPUT', @count OUTPUT
select @count