The amount with which the copy-trader will enter the strategy will depend on the method that the trader is using to enter. If the trader will use a fixed amount when he enters the trade then the copy-trader will enter with the same amount (example: Trader put a fixed amount of 1000$, the trader will enter with the same amount) If the copy-trader does not have enough funds to mimic this amount then the copy-trader's account will compensate with leverage. If this still will not be enough then the trade will fail.
If the trader is using the % of the portfolio, then the copy-trader's account will use the same % from the available balance. (Example: Trader has 1000$ on his balance and copy-trader has 100$ on his account. If a trader trades 50% of his account this will mean that he will enter with 500$ and the copy-trader with 50$). In this case, the leverage will be only used if the trader has inputted any leverage in his strategy.