Time locale problem

Only in a laptop have a time difference of 6 hours more than the local time. The regional settings of the laptop are correct (Buenos Aires, Argentina), and the laptop displays the time correctly on the taskbar.
On the other hand, and less importantly, in a mobile phone it shows the hours in am-pm format, while in another laptop it shows them in 24 hour format.

  1. What do I have to modify in Windows 10 so that it takes the correct time?
  2. Is there a way to unify the time zone and the way to present the dates, from some configuration of the app?