VYM is an index fund that tracks the FTSE High Dividend Yield Index invests in global equities (excluding REITs) with high dividend yields. About 1/3 of the current index is in 10 stocks all US: Microsoft Corp., Exxon Mobil Corp., Johnson & Johnson, JPMorgan Chase & Co., Wells Fargo & Co., General Electric Co., AT&T Inc., Procter & Gamble Co., Pfizer Inc. and Chevron Corp.

QYLD is even more exotic. It seeks to track the CBOE NASDAQ-100 BuyWrite Index. That index in turn seeks to track the performance of a theoretical portfolio of the 100 largest NASDAQ stocks on which covered calls are written with a certain formula. Covered calls are a type of options strategy.

I'm just another rando on the internet, but I would recommend neither VYM nor QYLD to people new to investing who aren't sure what to buy. VTI is a far more appropriate suggestion. As would be VT (like VTI but looking at all stock markets), BND (index fund for US investment grade bonds), and maybe BNDX (ex-US investment-grade bonds with currency hedges)

I'm just another rando on the internet, but I concur with bradleyjg. Consider reading some of John Bogle's books or reading the Bogleheads wiki page. You cannot go too wrong with (VT / (VTI+VXUS) ) + BND.

BND is composed very heavily (~66%) of US Government bonds. It's largely effectively like just buying treasury bonds. Worth considering to instead get a corporate bond index fund + muni bond fund.