Where to focus more .Net framework Or the .NetCore from Job interview

for interview pupose both are important

it depends upon the company you have applied in , if they still work on web forms then they may ask you asp.net life cycles, if they work on mvc then they will ask you difference between webform and MVC and if they wprk on core they will ask about MVC and core.

apart from that core concepts like OOPs, web API, ADO.Net , EF, SQL are common in all types of interview.

also you should have knowledge of source controls like TFS and Git .

Azure is a plus .