How do I move a folder into another folder in My Folders?

It is easy to do so What ever Folder you want to move there just right click on it in the file which it give you click on Cut and then go to the Folder where you want to store it click right on yoru mouse and then past it most do it for you

It works different if you are in Yahoo. Moving new items into a preset/main folder: 1. Check the box next to the email you wish to add to this folder. 2. Go to the top and click on "Move." 3. Scroll down the drop down list that opens and click on the title of the folder you wish to add it to. That's all there is to do. It's gone from your email list and in the folder you selected.

Just click and drag those other folders into that main folder. Simple :)