I like having local Spotlight indexed "standard" file format archives of completed tasks and calendar items. This is not a popular feature for most people so it's not widely supported. Today I found that this is possible with Microsoft To Do [1] (which replaced old Outlook Tasks).
Microsoft's free To Do.app for macOS has a web store that is shared with Outlook.com (and with Outlook for macOS, but I did not want to install that even though I have a 365 family account).
To Do has no print or archive facility. However Outlook.com does and it shares the To Do sync data. (I think Outlook.com is free for anyone who has a Microsoft ID.)
So:
- Go to outlook.com and open task list (same Microsoft ID as To Do)
- View All or Completed or whatever list and click ellipsis to see print
- When Print choose to include notes.
I get a multi-MB decently formatted PDF that Spotlight indexes for me.
In the general Outlook.com view has print capabilities the To Do app lacks.
[1] To Do is the only Microsoft product I routinely used. They bought it from somebody a decade or so ago. I could now switch to macOS Reminders but I find it oddly useful to keep Reminders as an aide to my declining short term memory and use To Do for small projects, shopping and so on. I put quite a bit of information in To Do notes and often find value in looking it up.