VBA: Loop through all files in a directory and convert them to PDF-files

ConvertWordsToPdfs.cls

Sub ConvertWordsToPdfs()

    Dim directory As String    
    directory = "C:\Wordup" ' The starting directory
  
    Dim fso, folder, files
    Set fso = CreateObject("Scripting.FileSystemObject")
    
    Set folder = fso.GetFolder(directory)
    Set files = folder.files
    
    For Each file In files

        Dim newName As String
        newName = Replace(file.Path, ".doc", ".pdf")
                
        Documents.Open FileName:=file.Path, _
            ConfirmConversions:=False, ReadOnly:=False, AddToRecentFiles:=False, _
            PasswordDocument:="", PasswordTemplate:="", Revert:=False, _
            WritePasswordDocument:="", WritePasswordTemplate:="", Format:= _
            wdOpenFormatAuto, XMLTransform:=""
            
        ActiveDocument.ExportAsFixedFormat OutputFileName:=newName, _
            ExportFormat:=wdExportFormatPDF, OpenAfterExport:=False, OptimizeFor:= _
            wdExportOptimizeForPrint, Range:=wdExportAllDocument, From:=1, To:=1, _
            Item:=wdExportDocumentContent, IncludeDocProps:=True, KeepIRM:=True, _
            CreateBookmarks:=wdExportCreateNoBookmarks, DocStructureTags:=True, _
            BitmapMissingFonts:=True, UseISO19005_1:=False
        
        ActiveDocument.Close
      
    Next

End Sub

You need to enable Reference Microsoft Word if not enabled. Thanks @sebnilsson, & @mvpjjf.

#same issue here. Error 424 any answers?

Sub ConvertWordsToPdfs()

    Dim directory As String
    Dim fldr As Object
    Set fldr = Application.FileDialog(msoFileDialogFolderPicker)
    With fldr
        .Title = "Select folder with Word files to export to PDF"
        .AllowMultiSelect = False
        If .Show <> -1 Then Exit Sub
        directory = .SelectedItems(1)
    End With
    
  
    Dim fso, newFile, folder, files
    Set fso = CreateObject("Scripting.FileSystemObject")
    Set folder = fso.GetFolder(directory)
    Set files = folder.files
    
    For Each file In files
        Dim newName As String
        newName = Replace(file.Path, ".docx", ".pdf")
        newName = Replace(newName, ".doc", ".pdf")
        'Debug.Print file.Path
        Documents.Open Filename:=file.Path, _
            ConfirmConversions:=False, _
            ReadOnly:=False, _
            AddToRecentFiles:=False, _
            PasswordDocument:="", _
            PasswordTemplate:="", _
            Revert:=False, _
            WritePasswordDocument:="", _
            WritePasswordTemplate:="", _
            Format:= _
            wdOpenFormatAuto, _
            XMLTransform:=""
            
        ActiveDocument.ExportAsFixedFormat OutputFileName:=newName, _
            ExportFormat:=wdExportFormatPDF, _
            OpenAfterExport:=False, _
            OptimizeFor:= _
            wdExportOptimizeForPrint, _
            Range:=wdExportAllDocument, _
            From:=1, To:=1, _
            Item:=wdExportDocumentContent, _
            IncludeDocProps:=True, _
            KeepIRM:=True, _
            CreateBookmarks:=wdExportCreateNoBookmarks, _
            DocStructureTags:=True, _
            BitmapMissingFonts:=True, _
            UseISO19005_1:=False
        ActiveDocument.Close
      
    Next

End Sub

see https://github.com/tobya/docto