Open Settings
Tap Sound & vibration
Tap Ringtone
Select the SIM card if prompted
Choose a ringtone from the list
Tap OK or Apply
To use a custom ringtone, tap Add ringtone or Local ringtone
Select the audio file from your storage
Tap OK or Apply
Set contact-specific ringtone by opening Contacts
Open the contact
Tap Edit
Tap Ringtone
Choose the desired ringtone
Save the contact