Where is the bookmark options in the game?

To add a book mark you can tap on a location in the world map to bring up the info box about it and then tap the icon with 3 stars on it next to the co-ordinates.

To find your bookmarks there is an icon on the left of the co-ordinates display at the bottom of the screen when in the world map Or you can tap on the co-ordinates themselves to open the input screen and then tap the bookmark banner icon to the right of the province entry.