Sorry, it doesn't make any sense without the rest of the code. I'd focussed on the problem piece.
Here's the full code
Sub FillForm()
Dim oCtrl As Control
Dim oCC As ContentControl
Dim lngIndex As Long
Dim strTC As String
With m_oFrm
For Each oCtrl In .Controls
Select Case TypeName(oCtrl)
Case "TextBox"
If oCtrl.Name = "txtName" Then
strTC = strConv(oCtrl.Text, vbProperCase)
Set oCC = ActiveDocument.SelectContentControlsByTag("Name").Item(1)
oCC.Range.Text = strTC
For lngIndex = 1 To oCC.Range.Words.Count
If oCC.Range.Words(lngIndex).Characters(2) = "c" Then
oCC.Range.Words(lngIndex).Characters(3) = UCase(oCC.Range.Words(lngIndex).Characters(3))
End If
Next
ActiveDocument.SelectContentControlsByTag("Name1").Item(1).Range.Text = oCC.Range.Text
' If explanation required, then add a paragraph either side of the entered text
Dim oRng As Range
Set oRng = ActiveDocument.SelectContentControlsByTag("Explanation").Item(1).Range
oRng.Collapse wdCollapseStart
oRng.MoveStart wdCharacter, -1
oRng.InsertBefore vbCr
Set oRng = ActiveDocument.SelectContentControlsByTag("Explanation").Item(1).Range
oRng.Collapse wdCollapseEnd
oRng.MoveStart wdCharacter, 1
oRng.InsertAfter vbCr
ActiveDocument.SelectContentControlsByTag("Explanation").Item(1).Range.Text = oCC.Range.Text
Else
ActiveDocument.SelectContentControlsByTag(Replace(oCtrl.Name, "txt", "")).Item(1).Range.Text = oCtrl.Text
End If
Case "ComboBox"
ActiveDocument.SelectContentControlsByTag(Replace(oCtrl.Name, "cbo", "")).Item(1).Range.Text = oCtrl.Value
End Select
Next oCtrl
End With
lbl_Exit:
Exit Sub
End Sub