For instance: 1:1000 leverage.
You got USD 10 in your account, by using USD 1 of margin buying USD 1,000 worth value of Fiat Currencies.
If your holding USD 1,000 value only worth USD 990, it wiped out your account.
Your balance USD 10 with 1:1000 leverage, you can buy USD 10,000 worth of value fiat currencies.
If USD 10,000 you are holding fall to USD 9,990, it wiped out your account.
Simple Money Management Structure:
You have USD 1,000 account with 1:100 leverage.
You need USD 119 of margin requirement for 0.1 STD LOT on EUR/USD.
If you BUY EUR/USD on 0.3 STD LOT, you have to use approximately 33% of your account balance, or USD 327 of your account balance as margin requirement.
If you put 30 pips SL on this trade and the trade don't work out, it means you have a loss of USD 90 of your account equals to 9% of your account balance.
Conclusion:
Many amateur didn't calculate by using this simple money management structure. In 1:100 leverage account, you are using only 33% of your account balance as margin requirement with 9% risk of your whole account balance in a single trade, especially they love 1:1000 leverage account. You can execute 2 more position with 1:100 leverage, in other hand you can even execute another 29 exact position with 1:1000 leverage. If 3 position is 27% risk of your account balance, how many risk you are taking with 29 position? Calculate yourself.

srry might be a lil bit redundant, what u mean is if i have 100 usd, i can use it to buy 10000usd or more size of volume? and then if somehow my investment is not working so well, and if it become -100 usd it will wipe my account?