If you are searching for a PDF, it is important to know the difference between editions:
Search for: "Macroeconomía - Paul Samuelson y William Nordhaus - McGraw-Hill 21ª edición" paul samuelson macroeconomia pdf updated
The blunt truth: A truly "updated" (2020+) Paul Samuelson Macroeconomia PDF is rarely available for free legally. The copyright is strictly enforced by McGraw-Hill. Most free PDFs circulating are the 1997 15th edition, which is useless for modern macroeconomics (it doesn't even mention the Euro properly). If you are searching for a PDF, it
Your best strategy: