Ubuntu – Can I change file systems inside of partitions within GParted

Note: You'll have to do this from a live USB/live DVD.

CAUTION: This will wipe data off the windows partition(s), and possibly (although very unlikely) your Ubuntu ones as well.

Open up GParted (click on dock, type in "partition"), type in your password. Right click on your Windows partition(s) and click on delete. Apply changes. After that right click on your Ubuntu partition(s) and click on re-size/move, re-size your partition by dragging either side of the bar. Move the partition by dragging the bar itself. Apply changes, and you're done. Reboot into your main Ubuntu, and enjoy.

As for the /home and /boot, read these:

making /boot partition after install

making /home partition after install

Since Windows systems support FAT32 and NTFS "out of the box" (And only those two for your case) and Linux supports a whole range of them including FAT32 and NTFS, it is highly recommended to format the partition or disk you want to share in either FAT32 or NTFS, but since FAT32 has a file size limit of 4.2 GB, if you happen to work with huge files, then it is better you use NTFS.

Just to add, if you do it with another type of partition like ext4, btrfs or any other that Windows does not support natively then the files will work in Ubuntu but not in Windows. Heck, in Windows if you try to access that drive it will offer an option to format the drive to NTFS. So this is the reason to stick with either FAT32 or NTFS.

You can actually do this from Ubuntu if you want using for example GPARTED which is found in the Software Center or the Disks utility which comes installed by default.

I even wrote an answer to the support NTFS has in Ubuntu. So no matter which one you decide, both will be supported between both systems and you can have a shareable partition/disk between Ubuntu and Windows.

For several security and performance related issues, /home should never be FAT32 or NTFS. For your case, you should create another partition (Either by taking free space not used by files from an already created partition or using another hard drive) and THIS partition should be the one that is formatted as FAT32/NTFS. This partition will also be the one that will share the information between both, Windows and Ubuntu, not /home. At the end it should look something like this:

HARD DRIVE 1

/sda1 - Windows (NTFS, FAT32)
/sda2 - Swap
/sda3 - Ubuntu (EXT4)
/sda4 - Shared partition between Ubuntu and Windows (NTFS or FAT32 Format)

This is just a rough sketch but I think it will give you the idea on how to make it so they share each other. If you happen to have 2 hard drives then:

HARD DRIVE 1

/sda1 - Windows (NTFS, FAT32)
/sda2 - Swap
/sda3 - Ubuntu (EXT4)

HARD DRIVE 2
/sdb1 - Shared partition between Ubuntu and Windows (NTFS or FAT32 Format)