If anyone can earn 1 BTC without any skills and without any investment, i am sure He/she won't teach the way!
There's no such that you can earn 1 bitcoin without any skills and without investments. This is the impossible thing though I'm not believing there's always a possibility but who on Earth will have this laziness and have a blessing of 1 bitcoin? Oh yes maybe it's possible by someone who has a golden heart and will just give it to him for free.
Without skills and investment you won't be able to get that large sum. Because no one gives something for free.
1 BTC is above 4000 dollars. Which is much higher than the average monthly wage worldwide.
The only way could be gambling and the chance will be closer to none.