How can I back up my iPhone before switching devices?

Did you do a backup to iCloud or a computer before the old phone was lost? If yes, things should automatically load upon restoring from the backup. If not, you will have to set it up again manually all over again, as well as possibly even losing data.

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

Make sure iCloud is activated. This will only help if you were using iCloud previously too. This document basically tells you how to sign into iCloud --> Set up iCloud on all your devices --> Set up iCloud on all your devices - Apple Support

Change which apps sync and store data with iCloud - Apple Support

Follow the instructions in these support articles:

Redownload apps and games from Apple - Apple Support

Redownload music from the iTunes Store on your iPhone or iPad - Apple Support

Redownload books and audiobooks - Apple Support

When transitioning from one iPhone to another, it's essential to note that the actual applications don't seamlessly transfer between devices. Instead, what is transferred is the app data, accompanied by links redirecting to the respective apps on the App Store.

Important Points to Remember:

1. App Data, Not Entire Apps: While Quick Start transfers app data, it doesn't transfer the entire app itself. After the transfer, your new iPhone will automatically download the compatible versions of those apps from the App Store.
2. App Compatibility: If an app is no longer available in the App Store or isn't compatible with the new iPhone's iOS version, the transferred app data won't be usable.
3. Content Not Transferred: Quick Start doesn't transfer certain types of content, including:
   1. iTunes and App Store purchases (like music or ebooks)
   2. PDFs downloaded directly to Apple Books
   3. Content synced from iTunes (like imported music or videos)
   4. Data already stored in iCloud (like photos, messages, or contacts)
   5. Data synced to email accounts (contacts, reminders, notes, calendars)
   6. Specific settings like Face ID/Touch ID, Apple Pay information, Apple Mail data, and Apple Music data.

By understanding these details, you can make informed decisions about transferring your data to your new iPhone using Quick Start.

If you connect to Wifi, doesn't necessarily mean you are connected to the internet. --> Internet not available WiFi and Cellular … - Apple Community