Mac storage basics · External storage and adding space
Can I use my iPhone or iPad as extra storage for my Mac?
Short answer: Not as a drive — iPhones and iPads don't appear as disks to a Mac. Use AirDrop or iCloud to share files, and an external SSD or cloud storage for extra space.
Not as a drive. An iPhone or iPad doesn't appear as a disk to your Mac, and their storage is usually smaller and pricier per gigabyte anyway. You can share files between them through iCloud Drive or AirDrop, but that's not the same as extra space.
For real extra storage, use an external SSD or cloud storage.