It depends on what input amount, format and quality you have. There are free / open source tools (like Tesseract), but if you would like to use them, some manu

It depends on what input amount, format and quality you have. There are free / open source tools (like Tesseract), but if you would like to use them, some manual or (semi-)auto preprocessing steps are very important (threshold / binarization, deskew, noise removal[1]) too get nearly comparable results to commercial tools. Some tesseract based solutions are better integrated with automatic preprocessing, you could take a look at Papermerge or other self hosted document management solutions[2]. There are also commercial SDKs around tesseract with good price point, like Vintasoft OCR[5], which supports automatic preprocessing and delivers a decent quality. If you don't mind having a (free) clicking adventure with small amounts of documents, you could also try the free verson of PDF X-Change viewer[3], which has a small but pretty good OCR to embedded PDF-Layer option which makes PDFs "searchable". But the embedded OCR data cannot be easily extracted. The best "no cloud" / offline solution I found, was Abbyy FineReader[4] which also has a command line tool, but if you really want a ready to use, easy and good quality solution, I would go with Google Lens (if you don't mind google) [1] https://towardsdatascience.com/pre-processing-in-ocr-fc231c6035a7 https://towardsdatascience.com/pre-processing-in-ocr-fc231c6... [2] https://github.com/awesome-selfhosted/awesome-selfhosted#document-management https://github.com/awesome-selfhosted/awesome-selfhosted#doc... [3] https://www.tracker-software.com/product/pdf-xchange-editor https://www.tracker-software.com/product/pdf-xchange-editor [4] https://www.pdf-xchange.de/pdf-xchange-viewer/ https://www.pdf-xchange.de/pdf-xchange-viewer/ [5] https://www.vintasoft.com/vsocr-dotnet-index.html https://www.vintasoft.com/vsocr-dotnet-index.html