Many great resources are freely available on the internet. I list some here for reference:
1. ETF.com ETF Guides
2. US SEC Investor.gov ETF section
3. iShares by BlackRock Education section
4. Vanguard ETF knowledge Center
5. State Street Global Advisors SPDR Education section
6. Invesco's ETF Education section
7. ProShares ETF Education section
8. PIMCO ETF Education section
Below I summarize the basic info about ETFs for myself to learn, courtesy of the above .
Readers beware: You should do your own homework and consult experts before you do any investments. Don't rely on blogs or random info you come across like mine.