Imagine you want to buy a toy but you're not sure which one you want. You ask your mom to help you and she says she'll help you pick the best toy for you. To do that, she asks for suggestions from different toy stores. She sends them a special letter called a "request for proposal" or RFP for short.
The RFP is like a letter that tells the toy stores what you're looking for in a toy. It asks them to send back their ideas for what toy they think you would like best. They can also tell your mom how much they think the toy would cost and how long it would take to get it to you.
Once all of the toy stores send back their ideas, your mom can look at all of them and decide which one is the best option for you. The RFP helped your mom get information on different toys and pick the best one for you.
So, a request for proposal is kind of like a letter that asks for information and suggestions on something you want to buy or do. It helps you make a better decision by getting ideas from different places.