To help narrow down any specific issues you might be facing, let me know: What is the file (.mp4, .mov, .mkv)? Are you encountering a specific error message ? What iOS version is your iPhone currently running?
If you do not have the Google Drive application installed, you can use the mobile browser version to download your media assets. Instructions for Safari: to google.com in Safari. Log in to your Google account credentials. how to download video from google drive to iphone
the download by tapping Download on the Safari pop-up. To help narrow down any specific issues you