sudo dpkg --configure -a (the system asked to execute this command) Configuring Secure Boot told this:
Configuring Secure Boot The system will assist you in configuring UEFI Secure Boot. To permit the use of third-party drivers, a new Machine-Owner Key (MOK) has been generated. This key now needs to be enrolled in your system's firmware. To ensure that this change is being made by you as an authorized user, and not by an attacker, you must choose a password now and then confirm the change after reboot using the same password, in both the "Enroll MOK" and "Change Secure Boot state" menus that will be presented to you when this system reboots. If you proceed but do not confirm the password upon reboot, Ubuntu will still be able to boot on your system but any hardware that requires third-party drivers to work correctly may not be usable.
I haven't got sting where I can change the password. How I can fix this trouble with password? I have to change it after this message not with command
sudo -i. passwd