Boa noite!!

Já usou a pesquisa do fórum???

Tente algo........

Option Explicit

Private Const theDrive As String = "C"
Private Const theDriveFormat As String = ":"
Private Const theDir As String = "pastaPDF"
Private Const theDirFormat As String = ""
 
Public targetpath As String
Sub Part_I_8634()

    If testDir = True Then
         'Sua Rotina
        Exit Sub
    Else
        MkDir targetpath
    End If
theEnd:
     '    Sua Rotina
    Exit Sub
End Sub
Function testDir() As Boolean
  
    testDir = False
    targetpath = theDrive
    targetpath = targetpath & theDriveFormat
    targetpath = targetpath & theDir
    targetpath = targetpath & theDirFormat
    If Dir(targetpath, vbDirectory) = "" Then testDir = False _
Else
    testDir = True
theEnd:
     'Sua Rotina
    Exit Function
End Function

Ou....

Sub AleVBA()
Dim rspCreate
If Dir("C:pastaPDF", vbDirectory) = "" Then
    rspCreate = MsgBox("Diretorio não existe, Você deseja Criar?", vbYesNo)
     
    If rspCreate = vbYes Then
        MkDir "C:pastaPDF"
    End If
End If
End Sub