Declare PtrSafe Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As LongPtr, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As LongPtr
Sub PrintPDF()
    Dim FolderPath As String
    Dim FileName As String
    Dim FilePath As String
    
    FolderPath = "C:\Users\PDF\"
    FileName = Dir(FolderPath & "*.pdf")
    Do While FileName <> ""
        FilePath = FolderPath & FileName
        ShellExecute 0, "print", FilePath, vbNullString, vbNullString, 0
        Application.Wait (Now + TimeValue("0:00:03"))
        FileName = Dir
    Loop
    Call CloseAdobeReader
End Sub
Sub CloseAdobeReader()
    Dim objWMI As Object
    Dim objProcess As Object
    Dim colProcesses As Object
    Set objWMI = GetObject("winmgmts:\\.\root\cimv2")
    Set colProcesses = objWMI.ExecQuery("Select * from Win32_Process Where Name = 'AcroRd32.exe'")
        For Each objProcess In colProcesses
        objProcess.Terminate
    Next objProcess
        Set colProcesses = Nothing
    Set objWMI = Nothing
End Sub

Call PrintPDF