Recover phone data after restore

Where was it backed up?

• If backed up to iCloud, then you have the option to restore your data from there when setting up the device.
• If backed up to a computer, you have the same option to use that backup to restore your data.
• If you used an iCloud service, such as iCloud Photos, your pictures will return to your device when it is set up with the same Apple Account, or you can login to the web portal of iCloud and download your pictures from there.
• If you did not backup your data at all, there is nothing to restore.

Read this support article to discover how to restore your iPhone, iPad, or iPod touch from a backup --> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

If you have been syncing your device to iCloud then signing into iCloud again will restore the data. You do not tell us anything about the scenario under which you need to do this. If you deleted a file that might be in iCloud you can try recovering it from the relative Recently Deleted folder.

Some things are not stored in a backup. Click on this link and read "About missing information after you restore your iOS device with iCloud Backup" -->

If you're missing information after you restore your iPhone or iPad with iCloud Backup - Apple Support

If you can't back up your iOS or iPadOS device to a computer or restore it from a backup --> If you can't back up your iOS or iPadOS device to a computer or restore it from a backup - Apple Support

Which iCloud.com features are available in the browser on your device --> Which iCloud.com features are available in the browser on your device - Apple Support

If you were not using iCloud to sync data, and you didn't back it up to iCloud or a computer, your data are gone forever unless you kept a copy elsewhere.