Hi Hassan!
I'm Jen, and I'd be happy to help you out with this issue.
The Print Title options including Rows to repeat is always disabled in the Print Preview's page setup. Display the spreadsheet in Normal view, go to Page Layout Tab and click on Print Titles.
I hope this information helps. If you have any questions, please let me know and I'd be glad to assist you further.
Best Regards!
Jen :)
Hi Jen!
Thank you for the response.
In the print setup, these should not be disabled, I guess it is a configurational error as one of the respondent also pointed that in Excel 2016, same configurational mistake / error was there, I have written to Microsoft via email and hopefully this configurational error will be fixed in the next updates in Excel 365.