Create EFI partition before installing Windows 10

Most likely, you won't need larger ESP (EFI System Partition). Windows OS loader is rather small and Fedora will most likely just install GRUB on ESP and place the rest of its boot files in /boot which will be on a separate partition anyway. Unless you're going to experiment with unusual Linux setups (like EFISTUB booting etc.), 100 MB should be sufficient.

If you want to have a larger ESP just in case, you can create one using Windows installation media before the partitioning step.

How to manually create ESP using Windows installation media

Before the partitioning step:

^{(Technically, you could also do this on the partitioning step and click Refresh afterwards.)}

1. Press Shift+F10 to open Command Line.
2. Type diskpart Enter. Diskpart will take a while to launch.
3. Type list disk Enter A list of disks will be printed. Note the number next to yours (most likely 0). Select that disk: select disk 0 Enter.
4. Create ESP: create partition efi size=500 Enter (500 is partition size in MiB).
5. Exit Diskpart: exit Enter.