A Bitcoin ETF is a fund that tracks the price of Bitcoin and trades like a normal stock. For many people it's the easiest on-ramp: you buy it in a regular brokerage account without handling wallets or keys.
The upside is convenience and familiarity. The trade-off is that you don't hold the actual coins — you hold a fund that tracks them, and you pay a small yearly fee.
If you want to own real Bitcoin you can move, spend, or put to work in a trading bot, a crypto exchange is still the direct route. Many traders use both: an ETF for a simple long-term position, and an exchange for active trading.
Whichever you choose, size your position sensibly. Bitcoin is volatile and past performance never guarantees future results.