To do simple stuff with text is easy. There are 3 methods for use with the clipboard, Clipboard.Clear , Clipboard.SetText and Clipboard.GetText().
The SetText method writes to the clipboard. Suppose you have a textbox (Text1) full of text, to save it to the clipboard is simply
To launch notepad with text from the clipboard, it's probably easiest to create a temporary file and launch using shell.
Open a new project, add a text box (text1) and a command button (command1) and this code:
Private Sub Command1_Click()
Dim sTemp As String
'retrieve clipboard text content
sTemp = Clipboard.GetText()
'save it to a temporary file
Open App.Path & "\temp.txt" For Output As #1
Print #1, sTemp
'launch this file in notepad
Shell "notepad.exe " & App.Path & "\temp.txt", vbNormalFocus
'delete the temp file
Kill App.Path & "\temp.txt"
There's a lot more functionality in the API, you might want to google around for this.