Simply put: the leverage effect is a multiplier of your trading results.
For example, if your leverage is 1:30, instead of a 1% profit or loss, you can do 30% profit or loss in a single day. In other words: leverage is the use of borrowed funds to increase one's trading position beyond what would be available from their cash balance alone.
Leverage: Up to 1:30 (requires a 3.33% margin) for retail traders
Forex contract size: 100 000 EUR = 1 lot in EUR
Required Margin for the retail trader, 3.33%: 3.33% x 100 000 euros = 3 330 EUR