Date format

m_tarler makes an important point by distinguishing between converting text into a real Excel date and simply changing how the date is displayed.

For your specific example, once Excel recognizes 01 11 2025 as a date, press Ctrl + 1, select Custom, and enter dd/mm/yy. The result will be 01/11/25.

If Excel treats the original value as text, convert it first using Data > Text to Columns, selecting Date: DMY to ensure it is interpreted correctly as 1 November 2025.

so you have 2 different things here:

a) it appears you have TEXT that you want to convert to a date (this assume you are NOT looking for a TEXT string that looks more like a date)

b) assuming you want an actual excel date value from a) above then how do you display that date value in that format

if instead you just want TEXT you can convert "01 11 2025" to "01/11/25" using REPLACE or LEFT,MID,RIGHT or other text functions.

a) there are 2 options:

To REPLACE the column of date you can select the column and then under Data select 'Text to Columns'

Then select Deliminated -> NEXT -> leave Tab selected ->NEXT -> choose Date and select MDY and -> FINISH

Excel should then recognize that text and REPLACE with actual date values.  You still need to do b) below to tell excel exactly the format you want to see those date values in.

Alternatively you can use a FORMULA to convert the TEXT to a Date Value and I would suggest 

=--SUBSTITUTE(A1," ","/")

where A1 is the cell with that text.  Basically you put it into a format Excel will actually recognize as a DATE using the SUBSTITUTE function and then the -- tell excel to try and force into a number/date value.  Alternatively you can more formally use the DATEVALUE function like:

=DATEVALUE(SUBSTITUTE(A1," ","/"))

b) you need to tell excel the actual format you want to see that date Value in.  So you can click on that cell and choose Date (but that will default into your country specific date format like m/d/yyyy) or you can select 'more number formats and then select Date on the left and for me it is about the 6th option on the right, but if it isn't showing you can always choose Custom and type "mm/dd/yy" into the custom format