Windows 10 has removed some useful features of older versions. The recent files sub menu of Start menu is one of such feature.
You can still access that 'Recent Files' with few easy steps.
1. Whenever you open the Windows Explorer with default settings, the lover pane will give access to "Recent files"
2. You can enter this address in Windows Explorer: C:\Users\your_user_name\AppData\Roaming\Microsoft\Windows\Recent
4. Execute the run command: %AppData%\Microsoft\Windows\Recent\
or also shell:recent
What other feature you want back in Windows 10?