Steps for creating a subfolder in outlook 2016 1. right click on inbox
2. select new folder
3. name the new folder
4. click the message
5. drag and drop in the folder
(correct order)

To help keep your emails organized, you can create subfolders or personal folders by using the New Folder tool.

1.Click Folder > New Folder.

2.Type your folder name in the Name text box. In the Folder Contains drop-down menu, click Mail and Post Items.

3.In the Select where to place the folder box, click the folder under which you want to place your new subfolder.

4.Click OK. The subfolder is created.

5.Tip: After you create a subfolder, you can move any of your emails to your new subfolder by dragging them from other folders and dropping them in the new subfolder. You can also right-click an email and select Move. Then choose the subfolder you want.

Explanation:

Hope it helps