There are tons of PDF apps out there but not all of them walk their talk. Only few provide really transformative user experience. When I talk about transformative experiences in the context of technology use in education I am primarily referring to SAMR model. The goal of integrating technology in our teaching, as I have repeated stated here in educatorstechnology.com, is to create radical transformative experiences where technology is not used as an add-on or a replacement of old traditional ways of teaching, but rather as a catalyst to drive deep and meaningful learning. The PDF apps I curated for you today, I believe, can be used in a transformative way to enhance your overall productivity. The original list published here 4 years ago contained 9 apps but upon revisiting it this month (November, 2021) I decided to omit some titles from this list cutting it down to only five apps. Some of the services provided by these apps include: read and edit PDFs, sign and request signatures from others, fill out forms, annotate PDFs, add highlights and comments, and many more. 1- Adobe Acrobat Reader A great app that lets you read, edit, and convert PDFs. Some of the main features it provides include: "Open and view PDFs with the free Adobe PDF viewer app. Search to find text fast in your PDF documents. Share files for commenting or viewing. Collect comments from multiple people in one file online. Add PDF notes and comments, including sticky notes and highlights. Write on PDF documents by adding text or drawings. Subscribe to edit text and images directly in your PDF. Fix a typo or add a paragraph with the paid PDF editor feature. Easily fill in PDF forms with the form filler feature. E-sign documents using your finger or stylus. Sign in to your free account to store and access files across devices. Access all your files by linking online storage accounts, like Microsoft OneDrive, Dropbox, or Google Drive Access scanned PDFs that you’ve captured using the free Adobe Scan app. Open your scans in Adobe Acrobat Reader to fill, sign, comment, and share." 2- Notability This is another excellent app that you can use to " take notes, sketch ideas, annotate PDFs, mark-up photos, record lectures, provide audio feedback and more. Some of its features include: Work with a variety of note-taking, journaling, and drawing tools like ink, highlighter, text, and audio. Mark up imported textbooks, documents, lecture slides, class assignments, and images. Instantly create notes from a selection of templates with customizable spacing and backgrounds. Explore endless ideas with continuous page scroll. Add photos, GIFs, web pages, and more. Record and playback audio Handwrite and sketch naturally Present ideas in full screen without distracting toolbars when connected to an external display. Work with two notes side-by-side. Import PDFs, DOCs, PPTs, images, GIFs, and more. Easily create searchable multi-page PDFs using the built-in Document Scanner." 3-PDFElement Lite Use this app to " read, edit, annotate, convert and sign PDF files on the go. Some of its features include: Font recognition Change font, size, color, and more. Single line or paragraph can be selected to move, cut, copy, paste or delete. Add text box, text call-out, stamps, freehand drawing and eraser. Highlight, underline or strike through context. Directly edit your PDF forms with ease; Sign your forms with handwriting signature Combine different format files into a new PDF. Import files from cloud storage including Dropbox,Google Drive,OneDrive,Box, or via WiFi wireless transfer. Quickly snap a photo of anything into a PDF and share with others. 4- PDF Expert: Reader, Editor App PDF Expert lets you read, annotate, edit, and fill out PDF forms. Some of its features include: "Quickly open PDF documents from email, the web, or any app that supports “Open In…” Enable full-text search, scroll, zoom in and out. Mark important info in books or documents with the first class annotation tools: highlight, underline, strikethrough and others. Insert predesigned stamps such as Approved, Not Approved, Confidential and more. Add comments to the texts you read using sticky notes and drawing tools. Fill out any PDF forms with interactive fields such as text fields, checkboxes and radio buttons. Edit or modify existing text. The font, size, and opacity of the original text are automatically detected, so you can make edits easily. Easily add, replace and resize images in your PDFs. Or change a logo or a graph. PDF Expert will handle those edits easily. Use e-signatures to sign contracts and agreements on the go. Sign documents with signatures synchronized across all your devices: Mac, iPhone, iPad." 5- iAnnotate 4 iAnnotate allows you to read, annotate, and share PDFs, Microsoft Office files, images and web pages! Some of its features include: "Annotate: Choose from the pen, highlighter, typewriter, stamp, straight-line, note, underline, strikeout, photo, voice recording, arrow, rectangle, circle, and date stamp tools. Customize: Drag and drop tools to your custom toolbars. Swipe between toolbars, or open the Toolbox to access all your tools. Access: Connect with Box, Dropbox, Google Drive, OneDrive (including OneDrive for Business) or open PDFs directly from email and other apps. Search: Search documents in your local library and throughout your cloud storage. Share: iAnnotate saves your markups directly to the PDF, so they can be viewed and edited in external PDF readers. Web markup: Open a web capture tab and find the site you want to mark up. iAnnotate will convert it to a PDF for annotation. Two documents: Work on two documents side-by-side, for even greater productivity. Create: Create brand new PDFs with blank, lined, or graph-paper pages. Secure: Full support for the iOS Data Protection and Keychain functions. Modify: Add, delete, rotate, and rearrange pages in your documents." This post originally appeared in Educational Technology and Mobile Learning ( www.educatorstechnology.com ).