How to transfer Videos from Windows into iPhoto gallery

Dear all, I just switched from Android to iOS and backed up all my files on my Windows laptop (since Move to iOS App didn't fully transfer everything). Now I want to put all my videos from Windows to my iPhone but iPhotos tells me that I can only upload .jpg format. How can I make sure that my videos also appear in my gallery? Because if I just put them on iCloud Drive I can't see them in gallery. Thank you very much for your support!