There is such a thing as an LOI (Letter of Interest or Letter of Intent) which many foundations use to determine if you are a good fit and if they should invite you to submit a full proposal. Maybe that's what the foundation's speaker meant by sending a 1 page introduction. What's important is to follow each foundation's posted guidelines which you can get through their websites or by calling them. Some foundations state that they do not accept unsolicited proposals. In that case you might consider the 1 page letter, but that alone rarely works to interest a foundation that is not open to reviewing unsolicted LOIs or proposals.