Hello @MrLalatg,
And welcome to the community!
To build your own OCR engine, please have a look here: Document-Processing-Code-Samples/SimpleOCREngine.cs at master · UiPath/Document-Processing-Code-Samples · GitHub . This entire repo on Github contains a dummy OCR engine, a dummy extractor and a dummy classifier.
On the OCR side, all you would need to do (for the basic functionality) would be to define such a class that extends one of the abstract classes we have prepared in the contracts.
Please let me know if you have any questions!
Ioana