How do i change rington on iphone3 - Apple iPhone Smartphone

Step 1: Go to Settings on your iPhone.
Step 2: Locate Sound & Haptics under Settings panel.
Step 3: Under Sounds and Vibrations Patterns, choose your own preferred sound you would like to change.
Step 4: Finally, tap Done to finish the change steps.

If you want to make custom ringtone for your iPhone, you can read on this tutorial to learn more: https://all-things-about-apple.blogspot.com/2021/05/how-to-change-iphone-ringtone.html

If you want to get how to change ringtones on iPhone 8, you can simply accomplish it on your iPhone 8. What you need to do is open your ringtone settings to set ringtones on iPhone 8. How to change ringtones on iOS 10? Let's see how.
1. To set ringtones on iPhone 8, you need to open the settings app.
2. Tap on "Sounds" and head to "SOUNDS AND VIBRATION PATTERNS", then press "Ringtones".
3. You will see a list of ringtones under "RINGTONES". Simply tap on the ringtone you want to change and you will see a tick before the ringtone name, which means you complete how to change ringtones on iOS 10.

For more details, check: How to Change Custom Ringtone on iPhone