You can only be signed into one Apple ID at a time, on a given device, for a given service. So for your iOS devices that would generally be a sign-in for iCloud (i.e. calendar, notes, iCloud drive, etc.), iTunes & App Store, and Messages. For most people that would almost aways be the same Apple ID across all 3 of those, but it could be different Apple IDs for 1 or 2 of those as well.
However, as pointed out, you cannot be signed into two Apple IDs for one of those services on a given device at the same time.
That being said there are some ways to share information between different Apple ID accounts on the same device. You could make a Family Sharing group with one Apple ID and have your second Apple ID join that sharing group. With Family Sharing you could share an iCloud storage plan between the two accounts, and share purchases from the App Store:
https://www.apple.com/family-sharing/
I would imagine though that one of your biggest desired would be to share Contacts and Calendars. You can do this indirectly by relying on an @icloud.com or @gmail.com account, for example, that all your devices could sync with regardless of which Apple ID they are signed in to. Here are three very different presentations on this exact method:
https://www.macworld.com/article/2013415/how-to-share-family-contacts.html
https://lenashore.com/2017/12/create-a-shared-family-address-book-with-contacts-and-icloud-2/
https://apple.stackexchange.com/questions/276183/how-do-i-sync-contacts-between-2-icloud-accounts
All that being said, I imagine on your Windows PC you'd have a calendar/contact client, such as Microsoft Outlook, tied into that "shared" common @icloud.com or @gmail.com account. So it's really less about employing a "Family Sharing" solution moreso than utilizing a common email (with calendaring and contacts service) that both your iOS and Windows devices can access/sync with regardless of which Apple ID they are signed into directly themselves.
That's how I would summarize and clarify the solutions as presented in those three tutorials.