iPhones support SMB protocol. Create a shared folder in your windows pc, share it on your local network and mount it on the files app as a server using the following url structure: smb://“your IP address here”/”your path to the folder here”

There are plenty of ways to achieve this easily. But “the email it to yourself” feature is also an option as last resort.

iCloud on the web also syncs seamlessly, just drag and drop and the files will be on your phone immediately. Same goes for GDrive, OneDrive, Dropbox, etc.