Dim bill As integer=textbox14.text
Module1.billno = bill
            Form18.txtbillno = Module1.billno

Value of Type 'Integer' cannot be converted to System.Windows.Forms.Textbox

Are you using data encapsulation or just sending to Module1's public variable?

(Encapsulation would be using public Properties)

Example:

'Declare local variable
Private iBill as Integer


Public Property CurrentBill as Integer
    Get
        Return me.iBill
    End Get
    Set (value as Integer)
        Me.iBill = Value
    End Set
End Property

-Or-

You can try the following:

Dim bill As Integer = TryCast(textbox14.text,Integer)
If IsNothing(bill) = False Then
    Module1.billno = bill
Else
    MsgBox("Cast not successful")
End If

No.in the module I declared all the varibles used in the whole application................

Dim bill As integer=textbox14.text

You have to convert textbox14.text from string to integer. One way to do this is

If IsNumeric(textbox14.text) Then
    bill = textbox14.text
Else
    'textbox14.text is not a number
End If

As for the rest, I'll assume the error occurred on line 3 (you didn't specify) and that the error is because txtbillno is a textbox in which case the code should be

Form18.txtbillno.Text = Module1.billno
Dim bill As integer=textbox14.text
Module1.billno = bill
Form18.txtbillno = Module1.billno

txtbillno is a textbox so u are getting the error....
u need to add .Text after the textbox object

Form18.txtbillno.Text = Module1.billno

I declare the varilble in form18 as

  Public tolal As Double

can't assign value to in from form7 as like this........

  Form18.total = Module1.dailytotalamount

but i got error as:
form18.total is not accessible in this context it is private ?

If the declaration is in anything private than it is in accessable.

Can you post the bit of code for the declaration?

this the way i hava assigned the varibles

  Public class form18
  Dim connectionstring As String = Module1.connectionString
    Dim sqlconn As New SqlConnection(connectionString)
    Public sqlDataset As New DataSet
    Dim myCommand1 As SqlCommand
    Public SQLdr As SqlDataReader
    Dim myConnection As SqlConnection
    Dim nxtmajor As Integer
    Dim sqlcmd As New SqlCommand
    'Dim dep As String
    Dim tbStudent As DataTable
    Dim total As Integer
    'Dim sname As String
    Public tolal As Double
    Public totdue As Double
    Public payed As Double
    Public bill As Integer
    Public mode As String
    Dim myCommand As SqlCommand

U have two variables

Dim total as Integer and it wont be accessible
Public tolal as Double is accessible

but in your code

 Public tolal As Double ' tolal is public
 Form18.total = Module1.dailytotalamount ' total is not public....

u have declared tolal as public but not total

Comments
What I figured! Very nice, pooja!
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