How to create function which return month April to march

Hey try this

    @dateFrom datetime,
    @dateTo datetime
   
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;
    declare @records table 
    ( 
      [ArrivalDate] datetime not null 
    ) 
    declare @dateIndex datetime = @dateFrom 
    while @dateIndex <= @dateTo 
      begin 
        select @dateIndex = dateadd(MONTH, 1, @dateIndex) 
        insert into @records select @dateIndex 
      end 

    select   r.ArrivalDate
    from @records r order by r.ArrivalDate asc
END