Building on top of Unity’s Tilemap functionality, a NavTile has an extra field to specify what type of area the Tile represents. Custom area types can be added through the areas tab in the NavTile Settings Window.
NavTiles can be recognized by their blue icon in the project hierarchy. This distinguishes them from Unity’s own Tiles, which have a purple icon.
You can create a NavTile through the “Create” menu, which is opened by right clicking in the hierarchy window. The NavTile option is located right below the Tile option.
If you already created Unity Tiles, or you don’t want to manually create tons of NavTiles for your sprite sheet, there are some tools available that can help you convert Tiles or Sprites to NavTiles.