How to print the title of a pages document? Instead of manually writing the title within each Pages document?

Apple is not attempting to compete with Microsoft with Pages, Numbers, or Keynote, nor is it attempting to "borrow" any Word features to enhance Pages capabilities.

Pages '09 v4.3 has an Insert menu : Filename feature but you still have to position the insertion point in the document before you select that menu item. However, the iWork '09 suite of applications are retired, and do not work on Catalina since they are 32-bit. When Apple rewrote Pages in Oct 2013 (as Pages v5.0), they dropped many features, including that Insert menu : Filename that was never replaced.

You can always provide direct feedback to the Pages product team via the Pages Application menu.

Can you clarify your comment? Still vague. What do you mean by print the title of a pages document?

The best non-coding solution that you can hope for, is to click the document window title, select the Pages document name there, copy to the clipboard. Then paste in your document body, or relevant header/footer location. Unlike Word, Pages does not have reserved variables (e.g. document name) that can be embedded in the document body and then filled automatically.