Download apps by Readdle Technologies Limited, including Spark Mail – Email by Readdle, Fluix - Docs & Task Workflow, PDF Expert: PDF Editor, Reader, and many more. Oct 29, · How to Use the Best PDF Expert Alternative for Windows. Step 1. Import the PDF Document. Launch the program on your desktop. To open your document, you can click the "Open File" button on the Home window, or you can simply drag and drop the file into the program window. Step 2.