,,,,, make that Outlook accepts the following phone format without changing
them by itself?

+54 (xxxx) xxxxxx  - 4 digits area code - 6 digits phone number

I do have my location in the modem set as 4 digits of area code, but once
the number is entered, if I click on that phone field, Outlook changes the
number adding the country code again, ending the number as +54 (54xx)
xxxxxxxx [an apparent phone number of 8 digits].

Same happens if number is +54 (xx) xxxxxxxx - 2 digits area code 8 digits
phone number
It ends up being +54 (541) 1xxxxxxxx

Jorge Enrique Knull