A lot of programs install side processes that run every time you start your PC, and some of them are not things you need running on your system all the time. Compared with Windows 7, in which you had to run the MSCONFIG utility, Windows 10 (and Windows 8.x before it) gives you a new, easier way to limit what runs at startup—from the updated Task Manager.
The easiest way to invoke the Task Manager is by pressing Ctrl-Shift-Esc.Switch to the Startup tab, and you'll see all the programs that load at Windows startup. The dialog box even has a column that shows you the Startup impact for each. The Status column shows whether the program is enabled to run at startup or not. You can right-click on any entry to change this status. It's usually fairly easy to see things you don't want to run. For example, if you never use iTunes, you probably don't need iTunesHelper to be running all the time.