Create a page in your document called "Titleblock", format it and place dummy content if desired. For each "sheet", just select it from Page Background (you can set an image, URL, or another page in the diagram). For filling out information which varies, just have one titleblock symbol and add Placeholders for the custom data attributes which you add to it as well. (See: https://www.drawio.com/blog/placeholders) This is a common workflow in CAD as well just with different terms; i.e. a linked titleblock layout used for all sheets and a block inserted into the actual drawing with the attributes filled out.