This is usually printed on the label of the router, but if the sticker is faded or the settings were changed, a wordlist is needed to brute-force it.
For (Maroc Telecom specific):
Yes, but only if you have never changed it from the default. If you changed it and forgot it, a wordlist is useless. You must physically reset the router (hold the reset button for 30 seconds using a paperclip). Wordlist Fibre Maroc Telecom-