I have a Form in wich I enter some values (project info)

The values entered in these fields, are stored in some variables in VBA when the user clicks the button:
Private Sub btnPItoKabels_Click()
Dim Project As String
Dim ProjectNummer As String
Dim OpdrachtGever As String
Project = ProjectInvoer.Value
ProjectNummer = ProjectNrInvoer.Value
OpdrachtGever = OpdrachtgeverInvoer.Value
DoCmd.OpenForm "frmMain", acNormal, , , acFormAdd
DoCmd.Close acForm, "frmProjectInvoer", acSaveNo
End Sub
Now I would like to retrieve these values in a few reports I have (they will appear in the header)

These are just regular text fields.
How can I retrieve the values from the three strings and put them in these fields?
OKbutton? How is it the Reports relate to this form?