Q: how do I FTP to IPAD Pro

Use iCloud Drive to transfer your data.

Set up iCloud Drive on all of your devices - Apple Support

iOS does not allow FTP, SFTP, SSH or any other similar type connection.  You can transfer files to apps via numerous cloud-based storage services (iCloud, onedrive, box, Dropbox, sugarsync, etc) or you can use iTunes (iTunes 11 for Windows: Transfer files between your computer and mobile apps).