Interesting my work WIn 10 doesn't have this option. Here are a couple of alternatives - MS OneNote is free and I use it a lot in a work context. This could be used as a diary. If you are OK with Google and have an account you could try Keep although it is more of a note taking app but you can set reminders.
Yes it does, called Microsoft calendar. If you sign up to a MS one drive account, free unless you store more than 15gb, you can keep it in the cloud and install one drive and ms calendar on your phone and have it synchronised to pc and phone.
If you use Google chrome and have a free Google account look under apps and open Google calendar, again that syncs to your phone, even to an iPhone if you set it up right.
I've used both methods, both equally good. Keep doesn't really do the job, if you get asked are you free on.... You need a proper calendar app. There are also many other providers with alternatives which run across platforms, search in Windows store.
Works on all my devices, syncs brilliantly, lets me import ical calendars (e.g. the F1 race series dates/times, that so far this year hasn't happened), schedules meetings, repeat events, etc., etc., and is free.