NASA the only direct source of information regarding Apollo missions!
You only have their word for it!
Over a million people witnessed every single Saturn V launch from the Kennedy Space Center, Florida. Next were the orbital observations; there are thousands of amateur enthusiasts that watch the night sky for satellites; including myself... www.satellitespotting.com Apollo 7 & 9 remained in earth orbit. These objects were the largest in orbit at the time and was seen as bright as the brightest moving star in the sky by thousands of observers.
During the other missions, once leaving earth orbit, amateur tracking became more specialised but not impossible.. follow this link for example.. Apollo Witnesses.
Another useful link Radio HAM Apollo 11
Apollo 8 was extensively tracked by amateurs and professionals as it was the very first time humans had left the earth's gravitational influence. Images of engine burns and fuel dumps were recorded often. The flight path was publicly announced, as were all the Apollo flights so tracking by others could take place.
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Then there was the Soviet Union. They received voice signals direct from each Apollo mission via radio telescopes and specialised satellite tracking ships. Some was relayed directly to the Kremlin. We haven't even mentioned the thousands of geologists that have examined the returned rock & soil samples either yet. NASA was not the only source of information from each Apollo mission at all! Don't listen to these conspiracy nerds. They just hope you never bother to examine each petty claim they make.
Below is the Yuri Gagarin tracking ship. Completed in 1971, it received voice communications from the later Apollo missions as a test; but mainly designed to help with their Salyut Space Stations and the planned Apollo - Soyuz link up in 1975.
If the Apollo missions were a hoax, then such tracking hardware would not have received any voice or telemetry from them and would have screamed HOAX! Why didn't they? Because they knew it was all genuine.