The Notes mod makes for keeping track of things easier in Minecraft. It adds a convenient note taking system by simply pressing N to bring up the GUI.
Then you create a new note by pressing ‘new’ and type away! You can easily save however many notes you want or need and access them at any time by pressing N again.
You can set the biome and coordinates easily by pressing the respective buttons. Plus to make things even more convenient with this mod you can pin the notes to the main screen so you can easily reference them without even opening the menu.