The box for the capacity is a text box. You can type on any value you want (that ... is supported, at least, so up to 1PB). As long as your provider has the free space for it.
Just remember that the largest cluster (allocation unit) size may be 64kb on most versions of Windows, which means 256TB volume, max.
Also, note that you may not want to have partitions/volumes that are larger than 63TBs, as Windows has issues with disk checking if the volume is NTFS and 64TBs or larger... You can partition and pool the partitions to avoid the issue, if needed... But ....