If you can open the file, there are utilities available on the internet
that will create a new version without a password, but I have no idea
what they do to any special features in the file. If you cannot open the
file you need to find software that will crack the password for you.
Whether you feel you can trust the software someone provides you to
crack passwords or remove security features from files you have on your
computer, not to try to crack your computer, your passwords any any
activity you do on the internet it up to you.