Setting datetime format for whole organization

Hello,

Date format on notes look different depending on user. I expect that the preferences from Options->Formats->Customize->Date or Time tab would affect appearance. But as my tests shows, it has nothing to do with notes.

I found a solution for on-premise but we currently use dynamics crm 2016 online, check the solution, it might help: community.dynamics.com/.../how-to-fix-the-date-format-in-crm-notes

For user A, Datetime format: 02.01.2017 15:38:26

For user B, Datetime format: 2/6/2017 3:38:26 PM
I'd like to fix datetime format option for whole organization. User A format is the one we normally have.