If you have Outlook, check out the printing setting options for the calendar.

What I want to do is design custom day planner pages using Word and get it to automatically insert the calendar dates. I don't really expect that it can, but...might as well ask.

I bind books as a hobby, so I literally want to make my own custom day planner. Maybe I'll just buy some refill pages and bind those.

Or you could print the ones that come with Outlook. They already have the date on them and you can easily print many many days at one time. In addition, you can go into Page Layout and specify some things like the header and footer, the paper, and the font, etc.

If you don't want to do that,
You can find VBA on the web to insert a future date, but I'm not sure how you would get it to place a date, insert a page break and then insert the next date and then another page break and the next date and on and on. But all things are possible with code I think.

Perhaps there is a template for this on the web somewhere, but I have never seen one that inserted calculated dates and page breaks like this.