As I don't have the part of kickstand that fell off somewhere, I'm thinking of buying a replacement kickstand. I assume that I'll need to remove the old kickstand and install a new one. Can that be easily done? What type of a kickstand should I buy? Is there something else I should take into notion when buying a kickstand, like different sizes etc?
Managed to find replacement kickstand that would fit my bike. In my case it was Ursus rear kickstand with 18mm fixing plate (there are also ones with 40mm fixing plate). Very simple to install with just two bolts.
Here is the catalog of Ursus kickstands: https://ursus.it/products/urban-city/kickstands/
That's a nuisance. Kickstands are usually adjustable, by being 'telescopic' to an extent. It looks like the lower part of it, which would extend, has come loose and dropped out.
Fortunately it is an adult size bike with full size wheels, so a replacement kickstand should be simple to install by attaching it and then adjusting the length. problems only normally arise on smaller wheeled, kids' bikes.
Simple to install, just use grease on the threads, but you will need to find one which specifically fits your frame in the same place. See how it is held on by two bolts. Most designs I have seen mount just behind the bottom bracket instead, i.e. central on the bike instead of at the rear wheel.
The easiest replacement will be with the same type in the same place. I don't know what term you would search for to get the same type you have already, sorry, there are a lot of designs.
Helpfully Focus have a page on their website with lots of designs available. If you can find one on there, great, but it should be fruitful for you to contact Focus customer support to find out which of their products are compatible with your frame. So not so much a product recommendation, as a hint towards Focus customer support.