For locations you navigate to frequently but are not available in the pre-defined 'Categories' in the search function, you can create your own custom list of Bookmarks

First, select the place you wish to bookmark - either by tapping and holding on the map, or after selecting a search result. Then tap the 'Save' button in the bottom toolbar. This will save the selected place to your default Bookmarks list, 'My Places'. 

The 'star' (Android) or 'starred list' (iOS) icons in the default toolbar will open your bookmarks, where you can find and categorise your bookmarks. To export/save them, use the three dotted menu icon to the right of the list you wish to export.