OCR software is not provided via any Mac, you purchase it either with your scanner or a stand alone application. OmniPress is the best but I am reluctant to tell you how much it costs.
*OmniPage* is currently the most advanced OCR engine for personal computers. Currently there is a Windows version, but the Macintosh version of OmniPage was discontinued over a decade ago. That product was written for PowerPC, so it won't run on a modern Macintosh.
Nuance, developers of OmniPage, offer this product for Mac users, which uses the full OmniPage engine:
PDFConverter ($100)
http://www.nuance.com/products/pdf-converter-mac/index.htm
PDFConverter does an excellent job of OCR (I own a copy), but Nuance is a horrible company to deal with, offering just about no service and support, with multiple reports of them screwing customers.
PDFpen ($75)
https://smilesoftware.com/pdfpen/?
includes much of, but not all of, OmniPage's OCR engine, and it does a quite decent job of OCR. PDFpen is a PDF editor with built-in OCR capability and it is a favorite among professionals who do a lot of work with PDF's, but who don't want to have to pay around $400 for Adobe Acrobat Pro/Mac. It's a good product from a good company.
There are a bunch of other OCR products for the Mac, or products that include OCR. A decent stand-alone OCR program is:
ABBYY FineReader Pro $120
http://finereader.abbyy.com/pro_for_mac/
Review:
http://www.pcmag.com/article2/0,2817,2430295,00.asp
http://www.documentsnap.com/ocr-smackdown-abbyy-finereader-vs-adobe-acrobat/
There is also this stand-alone OCR program:
ReadIris $140
http://www.irislink.com/EN-US/c1466/Readiris-16-for-Macintosh---OCR-Software.aspx
https://www.amazon.com/dp/B00HCORAUU/?tag=macforums0e4-20
which is *not* a highly regarded product compared to the others.
If you want something that is low cost, consider:
PDF OCR (free/$30)
http://solutions.weblite.ca/pdfocrx/
which relies on the open-source OCR engine Tesseract.
If you would like a list of products that do OCR, just let me know. There are a bunch of them. But the above ones are most noteworthy.