Does your FN key on the keyboard have a small light on it?
If so, FN Lock is turned on.
If it's the same as my HP, you can press the Shift key to turn it off. Press the FN key and Shift turns it on.
If the above doesn't help, then which browser is this for? I'll post back steps on how to toggle this on/off in its Settings page.
https://www.elevenforum.com/t/turn-on-or-off-caret-browsing-in-microsoft-edge.23898/