You should use the Outlook editor e.g. as follows, however I would strongly urge you to use the code from http://www.rondebruin.nl/win/s1/outlook/openclose.htm to start Outlook properly, whether it is running or not.

Sub Macro1()

Dim inputData As String
Dim OutApp As Object
Dim outMail As Object
Dim olInsp As Object
Dim wdDoc As Document
Dim oRng As Range

    inputData = InputBox("Your number", "Input number")

    Set OutApp = CreateObject("Outlook.Application") 'Set OutApp = OutlookApp()
    Set outMail = OutApp.CreateItem(0)
    On Error Resume Next
    ' Change the mail address and subject in the macro before you run it.
    With outMail
        .To = "yourname@yourname.be"
        .CC = ""
        .bCC = ""
        .Subject = inputData
        .Display
        Set olInsp = .GetInspector
        Set wdDoc = olInsp.WordEditor
        Set oRng = wdDoc.Range
        oRng.Collapse 1
        oRng.Text = inputData & vbCrLf & _
                    "kind regards" & vbCrLf & _
                    "My company name" & vbCrLf & _
                    "My company adress" & vbCrLf & _
                    "My company city"
    End With
    Set OutApp = Nothing
    Set outMail = Nothing
    Set olInsp = Nothing
    Set wdDoc = Nothing
    Set oRng = Nothing
End Sub