Donationware is like buying toys from a store, but instead of paying a fixed price, you get to choose how much you want to pay for it. It's like when someone gives you a gift and you want to thank them by giving them some money because you really appreciate their gift.
So, when you download a donationware, you are getting a piece of software or a program that someone has made and they are letting you use it for free. But, if you really like it and want to support the creator, you can choose to donate some money to them.
It's like when you go out to eat and the waiter or waitress does a really good job, you might want to leave them a little extra money as a tip. In this case, the person who made the donationware is doing a really good job and you want to show them that you appreciate their hard work by giving them a little extra money.
Donationware is a way for creators to offer their work for free but still get some support from the people who enjoy it. And it's a way for people to show their appreciation for something they really like by giving a voluntary contribution.