When Buying a call, you have the right (but no obligation) to buy a security at a predetermined price. When Selling a call, you have an obligation to deliver the security at a predetermined price to the option buyer if they exercise the option. In this case, shares that you own would be called away in an assignment.
Likewise, when Buying a put, you have the right (but no obligation) to sell a security at a predetermined price. When Selling a put, you have an obligation to buy the security at a predetermined price from the option buyer if they exercise the option. In this case, you would be purchasing the shares of the underlying security in an assignment.
All Olive strategies are designed such that they do not require the investor to pay options premium. The sell side legs help finance the call side legs to leave a net credit at inception. In other words, you can make the bet for free today (or even get paid), but you will need to have money in your account for margin purposes