The right hand end of the task bar at the bottom of the screen is now called the notification area (it used to be the system tray).
Some programs and settings put icons in the notification area to give you quick access to them.
But then Windows decides to hide some of them behind a little up-pointing chevron. (I don't know why)
If you want to show them all, or select which to show and which to hide, then:
Left click the Start button, then the cogwheel icon labelled "Settings", then the "Personalisation" box, then, at the bottom of the left hand column, the word "Taskbar".
Scroll down to the heading "Notification area", and left click on the words "Select which icons appear on the taskbar".
Underneath the words "Always show all icons in the notification area" is an on/off button - left click it to switch them on or off.
Or use the individual on/off buttons to the right of the listed names.
Left click the cross in the top right hand corner of the box to finish.