How do I get my contacts after erasing my iPhone?

If you were using iCloud to sync contacts, sign into iCloud again.

If you were not using iCloud, restore your device from a backup.

Read/watch these links -->

If you see the Restore screen on your iPhone, iPad, or iPod touch - https://support.apple.com/HT203122

Click on this link to discover how to 'Restore your iPhone, iPad, or iPod touch from a backup' --> https://support.apple.com/HT204184

or watch this video if you're using a Mac to do this:

https://www.youtube.com/watch?v=Jbp3gGTQygg

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" -->

https://support.apple.com/HT203768