To change the password for the root user or any other user on OpenBSD, you can use the passwd command.
To change the password for the root user, you can run the following command as the root user:
passwd
You will be prompted to enter the new password twice. Note that when you type your password, no characters will be displayed on the screen. This is a security measure to prevent others from seeing your password as you type it.
To change the password for a different user, run the same command as the root user and specify the username as an argument:
passwd username
Again, you will be prompted to enter the new password twice.
After changing the password, you should verify that you can log in as the user using the new password. If you are unable to log in, you may have mistyped the new password, in which case you should repeat the process and enter the new password carefully.
It is recommended that you change your password regularly to help keep your system secure.