: Use the Print function in your web browser and set the destination to Save as PDF . Some tools allow you to define a "Single Page" layout to avoid page breaks.

: In Acrobat, you can manually input dimensions in the width and height fields if your specific "long" paper isn't a standard preset. Creating a Very Long Single-Page PDF

: Professional tools like Adobe Acrobat allow you to increase the "MediaBox" values up to 200 x 200 inches, creating an exceptionally large single page. Managing Large PDF Downloads