When you search for a word in a PDF without success, your PDF is most likely a scanned or image-based document. All text in scanned PDF are saved in bitmap image format and cannot be searched, copied or modified. To convert a PDF to searchable PDF, you need to process OCR on the scanned PDF first.
6 solutions to convert a scanned or image PDF to searchable PDF are introduced in this post, helping you to turn your PDF to searchable text easily with original formatting retained.
Cisdem PDF Converter OCR
Free Download macOS 10.13 or later 
Free Download Windows 11/10/8/7We prefer to use dedicated OCR programs to convert PDF to searchable PDF, because they are far more efficient than other possible solutions: they convert accurately with original formatting retained, they support batch convert PDF to searchable PDFs, they convert fast, they support many languages...
What should we use to convert scanned PDF to searchable PDF on Mac or Windows?
Cisdem PDF Converter OCR is definitely a feature-rich converter worth trying. It is an application to create and convert PDF files, having excellent support on different input and output formats. With its OCR feature, you can convert scanned PDF and images to searchable PDF, to editable Word, Excel, PowerPoint, EPUB, HTML, Text, and RTF format, no matter if your file is in English, Chinese, German, French, Spanish, Japanese or others.
Whether you are a beginner who has never tried PDF-related software or an office worker who often handles scanned documents, whether individuals or businesses, Cisdem PDF Converter OCR provides a stylish interface with straightforward guide, rich features, intelligent recognition technology and advanced settings, allowing everyone to save time and improve efficiency.
We know that most of the PDF-related products on the market like Adobe Acrobat only provide a 7-day free trial. To truly experience the functionality of the software, users can get a 14-day free trial version of Cisdem on Mac or Windows without any restrictions. Also, you can get a lifetime version of this product for just a few dollars, so it’s the king of bang for your buck!
Free Download macOS 10.13 or later Free Download Windows 11/10/8/7 
Also, there are various free tools available to convert scanned and image PDF to searchable PDF with OCR, the conversion accuracy will be lower than professional OCR programs, but still worth a try.
Convertio is an online free platform supporting file conversions on video, audio, image, ebook, font, document and so on. Convertio OCR is a part of Convertio conversion services, allowing users to convert scanned files in PDF and image format to searchable PDF, Word, Excel, PowerPoint, Text, RTF, CSV, ePub… It supports batch conversion and recognizing 50+ languages, but you can convert 10 pages for free, for more pages, you have to pay.
Online2pdf is a free tool to create, convert, organize and edit PDF files. It helps to convert unsearchable PDF to searchable PDF, Word, Excel, PowerPoint, Text and ebook format. 20+ file languages can be recognized by this program, but you can only convert 20 pages for free OCR services. One thing that differs online2pdf from Convertio is that, online2pdf allows users to protect, merge and compress the searchable PDF output.
In addition to online free searchable PDF converters, there are some reliable OCR freeware like FreeOCR and SimpleOCR. Since the latter only supports scanned images and the conversion effect is mediocre, we prefer FreeOCR with richer formats and more powerful OCR functions. Moreover, it now supports importing directly from Twain and WIA scanning drivers, PDF files and mainstream image formats.
If you have installed Adobe Acrobat Pro DC, conversion of scanned PDF to searchable PDF can be even easier, since Adobe can auto detect a scanned PDF and recognize the text with Adobe OCR. Also, being a powerful PDF editor, you can revise the OCR errors or edit the PDF file freely.
Bluebeam is a professional software to create, markup, edit and organize office & project documents, including PDF files. It has an OCR feature to turn scanned PDFs into searchable PDF, offering multiple configuration options to recognize different languages, OCR different document types and optimize OCR result as per your need. There is both single and batch mode that can greatly enhance the efficiency of OCR processing.
However, Bluebeam has discontinued its development for Mac versions since 2020, so you can only convert scanned PDF to searchable PDF with Bluebeam OCR on Windows platform.
tips: to batch convert scanned PDF to searchable PDF on Windows in Bluebeam, go to File > Batch > OCR, adjust the OCR settings and click OCR.
For the solutions to convert PDF to searchable PDF, we can go on and add more tools onto our recommendation list. Also, today, more and more users are willing to pay for a professional PDF converter with OCR feature, because such a program just brings what users expect, accurate conversion result, auto task, batch support, saving as other formats for future needs...
So, which one do you choose to convert your scanned PDF files?
Jose specializes in reviews, how-to guides, top lists, etc. on PDF, data recovery and multi-media. On his spare time, he likes to travel or challenge some extreme sports.
Katherine
I used to rely on some free tools to convert scanned documents, but they didn't work as I expected. As you said, we still need a professional converter.