List all devices
lsblk
Look at the UUID of your Windows 10 partition, for exemple:
sudo blkid /dev/sda2
Then edit /etc/grub.d/40_custom, and at the end of the file add:
menuentry "Windows 10" --class windows --class os {
insmod ntfs
search --no-floppy --set=root --fs-uuid $your_uuid_here$
ntldr /bootmgr
}
Run the following command to update grub config
grub-mkconfig -o /boot/grub/grub.cfg