In the following example, as you can see in the photo, Number of the week in the year can be identified by the ISOWEEKNUM function.

=ISOWEEKNUM("01/02/1900")----->>>>answer is 1
=ISOWEEKNUM("1-Jan-2020")----->>>>answer is 1
=ISOWEEKNUM("2-Jul-2020")----->>>>answer is 27
=ISOWEEKNUM("3-Sep-2021")----->>>>answer is 35
=ISOWEEKNUM("4-Apr-2022")----->>>>answer is 14
ISOWEEKNUM function
The ISOWEEKNUM function is one of the Date & Time functions of Excel.
It returns the ISO week number in the year for a given date.
ISOWEEKNUM arguments
=ISOWEEKNUM("Date")----->>>>Number
This function has just 1 Argument:
The argument of ISOWEEKNUM function is date.
The argument of ISOWEEKNUM function is required and not optional.