Back up your contacts on your old phone
Make sure both phones are charged and connected to Wi-Fi
Sign in to the same account on your new phone
Turn on contact sync in your account settings
Restore your backup on the new phone
Use a SIM card transfer if your contacts are stored on the SIM
Export your contacts as a file from the old phone
Import the contacts file on the new phone
Use a phone-to-phone transfer app or built-in transfer tool
Check that all contacts appear correctly on the new phone