# Advanced guides

- [QR codes](/advanced-guides/qr-codes.md)
- [Save handlers](/advanced-guides/save-handlers.md): Manipulate your PDF documents after they have been rendered.
- [Error handling](/advanced-guides/error-handling.md): Catch them all!
- [Signing a PDF](/advanced-guides/signing-a-pdf.md)
- [PDF Standards](/advanced-guides/pdf-standards.md)
- [ZUGFeRD](/advanced-guides/pdf-standards/zugferd.md): Zentraler User Guide des Forums elektronische Rechnung Deutschland
- [PDF/A](/advanced-guides/pdf-standards/pdf-a.md): PDF/A-1B (ISO 32000-1)
- [PDF/UA](/advanced-guides/pdf-standards/pdf-ua.md): PDF/Universal Accessibility (ISO 14289)
- [PDF/X-4](/advanced-guides/pdf-standards/pdf-x-4.md): Create print ready documents
- [Color profiles](/advanced-guides/color-profiles.md): Separation / DeviceN color support
- [JavaScript](/advanced-guides/javascript.md): This is an experimental feature and script tags may change in the future. However, please give it a try and feel free to provide feedback.
- [Common Object/Classes](/advanced-guides/common-object-classes.md)
- [createPdf function](/advanced-guides/common-object-classes/createpdf-function.md)
- [HtmlToPdf](/advanced-guides/common-object-classes/htmltopdf.md)
- [Result Object](/advanced-guides/common-object-classes/result-object.md)