Siri
To set up siri and without use head phone or Bluetooth directly use set up settings
iPhone 5s, iOS 12
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You do not need Headphone or Bluetooth for setting up Siri.
Retrain Siri with your voice
Go to Settings > Siri & Search, turn off Listen for “Hey Siri,” then turn on Listen for “Hey Siri” again. To change Siri accessibility settings, see Use accessibility features with Siri on iPhone.