Often you may be creating events or tasks with the same locations. Informant provides a feature that lets you create a bookmark. When you tap on the Map button next to the locations text entry, you can do a search of the location. Then select that location pin and press the + sign. It will create a bookmark.
From then on you can use that bookmark by simply typing its name in the location field or tapping on the map icon and then selecting the bookmarks icon on the top right.