codice:
Dim Riga As String
Dim NumFile As Integer
NumFile = FreeFile
Open File For Input As NumFile
While Not EOF(NumFile)
Line Input #NumFile, Riga
LeggiFile = LeggiFile & Riga 
Wend
Close (NumFile)
End Function

Private Sub Command1_Click()
RichTextBox1.Text = LeggiFile(App.Path & "\file.txt")
End Sub

codice:
Dim nuovonome
dim var as string
nuovonome = App.Path & "\file.txt"
var=RichTextBox1.Text
open nuovonome for output as 1
  print #1,var
close