I have installed Maliit Virtual Keyboard and selected it in System Settings; keyboard/virtual keyboard/Maliit.
Once I have entered a password Maliit works fine but I cannot access it to enter my password at log-on.
Is there a setting that I have missed or do I need to be editing a config file somewhere?
Any suggestions please.

OK I have done a little searching and come up with a single modification to a conf file that seems to do what I need for the moment. If there is a better way of making the keyboard work at logon then please let me know.
sudo nano /usr/share/sddm/sddm.conf.d/10_solus_default.conf
Then edit the input method of "[General]" to add qtvirtualkeyboard like so.

[General]
InputMethod=qtvirtualkeyboard

Edit: At the moment I am using QT Virtual Keyboard to input log-on password and then after the Plasma session has started Maliit Virtual Keyboard takes over. There was not an option to select QT Virtual Keyboard from within System Settings or an option to use Maliit for log-on.
Can't help wondering if there is a more elegant way without using this two program set-up.

9 days later

My mistake, should not have been editing files in /usr/ so instead run

sudo nano /etc/sddm.conf

Then add the following to the beginning of the file.

[General]
InputMethod=qtvirtualkeyboard

Modified my own files to match this, everything working fine.
Edit: Should also point out that these settings only seem to work for Wayland, switching to X11 stops both touch keyboards. Not looked into a solution for X11 as I only use Wayland.

    BuzzPCSOS I did that on laptop to disable the touchscreen
    but was different file. (commented out the input method for touchscreen)
    I kept poking screen causing issues..lol

        Axios You were probably not on Solus Plasma, all the touchscreen stuff needed to be installed and enabled there. Not really that much work but it still took a bit of poking around to find out what I needed to do. Fedora enables most of the touch features out of the box which seems to cause problems for many touchscreen laptop users.
        I have changed my hardware and now have a Solus Plasma Tablet with a detachable keyboard which is all working very well.