"Required investment" refers how much cash is needed to be held in your margin account to secure the outcome. It also represents the maximum amount you can lose on that outcome strategy.
All Olive strategies are designed such that they do not require you to pay options premium. The combinations are different legs act to either be neutral or receive premium. When you execute the outcome trade, your account balance will show no change (or you may even get paid). The "required investment" is the amount of options purchasing power you need in your account to secure the trade in the event of a margin call. This is also the maximum amount of cash you can lose on the outcome if the price of the underlying asset drops to zero.
This cash is used to satisfy the obligation to buy the underlying stock shares in the event that a short put position gets assigned. Short put positions are typically assigned if the underlying stock price drops below the price of the put, which is at or near the breakeven price of the outcome. You would then be exchanging the cash for shares of that stock. Olive strategies do not allow for naked short calls at this time, regardless of option approval level.