I just tried this on Ubuntu 18.04... At first, nothing seemed to happen after entering the password, but then after a second or two, I see this:
It's possible that you are missing some libraries that are required for generating the GPG key... it might pay to try creating it on the command line, so you can see any errors generated... open a terminal window and type:
Then follow the instructions... note that it might take quite a while (as in minutes) once it says:
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
But eventually you should see something like:
gpg: key D13FDC40CA81AD27 marked as ultimately trusted
gpg: revocation certificate stored as '/home/hcp/.gnupg/openpgp-revocs.d/9D90F94ED322D4FC62C285AFD13FDC40CA81AD27.rev'
public and secret key created and signed.
pub rsa3072 2020-09-28 [SC] [expires: 2022-09-28]
9D90F94ED322D4FC62C285AFD13FDC40CA81AD27
uid Command Line Test <bob@builder.com>
sub rsa3072 2020-09-28 [E] [expires: 2022-09-28]
And the key should be automatically added to the list in the "Passwords and Keys" application as well: