It depends on the version of Microsoft Word file format:
Word 2-95-(the French edition 97): uses relatively weak protection, hence a file can be cracked instantly no matter how strong a password is.
Word 97-2003: uses a short encryption key of 40 bits. Guaranteed cracking by merely finding the encryption key without searching for the password.
Word 2007-2021: uses highly secure and strong protection with no security holes. To crack such files you will have to try every possible password until
the correct one is found (brute force attack, dictionary attack). GPU acceleration is also an option.
However, life if full of blunders, and people will always be using weak passwords.