Point to note: Depending on your purchased theme, screenshots can vary.
You can set a common featured image for all pages/posts from 'Theme Options > Header > Short Header > Inner Page Banner Background'.
Point to note: Subtitle is not available for all themes.
If you want to set Title, Subtitle and Featured Image and pages/posts individually, then you can do so by following below steps:
1) For Blog and Blog details page (Blog single) from 'Blog' page.
2) For Team and Team details page from 'Team' page (Page link should be your-domain/team).
3) For Portfolio and Portfolio details page from 'Portfolio' page (Page link should be your-domain/portfolio).
4) For Case Studies and Case Study details page from 'Case Studies' page (Page link should be your-domain/case-studies).
5) For search page from 'Theme Options > Pages > Search'.
6) For all other pages, you can change Title, Subtitle and Featured Image from their own page.