You can invest in ETFs on the WSE, on European markets and in the USA. You can use Polish or foreign brokers. There are two types of accounts: regular (taxable) and retirement (IKE and IKZE). Where to invest in ETFs and how to choose a brokerage house? In addition to the recording, there is a “Transaction Cost Calculator” for download, which makes it easy to compare brokers.
Audio version (podcast)