Bitcoin's ledger is a public spreadsheet with aliases. Nobody writes your name next to the payment, but every input, output and amount is printed for anyone who wants to read. Given enough time and a few exchange records, aliases stop being aliases.
Monero attacks all three parts of a transaction at once. Ring signatures mix your input with decoys so the reader cannot tell which coin you actually spent. Stealth addresses mean the receiving address on the chain was generated fresh for this payment and appears nowhere else, not even in your own history. And amounts themselves get hidden behind commitments, so even the value isn't public.
The practical effect: an outside observer with the full chain still cannot draw a line from your purchase to your salary. Nobody is forced to opt in, it isn't a toggle, every transaction on the network does all of this. That's the difference between privacy and a privacy feature.
The cost is that audits get harder. Regulators dislike a ledger they cannot trace, which is why some exchanges quietly dropped it, and the coin spends most of its energy on exactly that tradeoff.
One habit if you use it: an XMR address starts with 4 or 8 and there is no shared format with anything else. Paste the full string into a code generator before sending anything, the same rule as every other chain, just with less margin for a mistyped character.