Question: how to transfer contacts from iphone se to iphone 8?
Answer: Tap the “Setting”> “iCloud”.
Sign in iCloud with the same Apple ID that you're going to use in the new iPhone.
When you signed in, turn on the “Contacts” and enable it to sync with iCloud.
Scroll down and tap “Storage & Backup”> “OK”> “Back Up”.
Wait until the backup process is complete.