Final Draft files (.FDX) act the same way as any other kind of file, so if you save your scripts into the cloud storage sync folder on your computer or iPad / iPhone, they should be uploaded to your online folder automatically (along with any other files that have been saved to that folder). When you're on your other device, open the local sync folder and the scripts (and any other files) you last edited on the other device should be there and fully up to date.
Don't have the script open on both devices at the same time.
Here are instructions from a few of the most widely-used providers:
- Apple iCloud: https://support.apple.com/lv-lv/guide/icloud/mm19ef899373/1.0/icloud/1.0
- Dropbox: https://help.dropbox.com/sync/sync-overview
- Google Drive: https://support.google.com/drive/answer/10838124?hl=en
- Microsoft OneDrive: https://support.microsoft.com/en-us/office/sync-onedrive-files-and-folders-d9262485-9bf8-4ceb-bac2-e83f68cb6a97
If you encounter any sync or saving issues, we won't be able to help -- it's outside our area of expertise. You'll want to contact your cloud storage service provider's technical support.