Outlook Microlearning: Display Week Number

 This is how to display Week Number in your Outlook Client Calendar View:

See https://support.microsoft.com/en-us/office/turn-on-or-off-week-numbers-in-month-view-and-the-date-navigator-194c16b6-c0be-4aad-a84a-2ad00f174e58 

Go to File->Options->Calendar-> Display Options

and check the "Show week numbers in the month view..." checkbox.

Then you can see in the calendar picker the week numbers:

Addendum:

Be careful how your first week of the year is configured.

Go to Options->Calendar->Work time->First week of the year and set to to "First 4-day week":

Source Week numbers in the Calendar are wrong - MSOutlook.info