No sound on call.

Hi ThatsNotLiam,

For help with the sound on your iPhone, try a normal restart of your device first. If needed, this article will help: Restart your iPhone. If the issue continues test the steps below found in the article here: If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker

"If you want to try more steps on your own

If you prefer, here are some more steps you can try on your own. After following these steps, you might still need to contact Apple Support to discuss service options.

1. Remove all screen protectors, films, or cases from your device. 
2. Check the speaker opening to see if it's blocked or dirty. On iPhone only, make sure that the receiver isn't blocked or dirty. 
3. If necessary, clean the speaker or receiver opening with a small, soft-bristled brush. Make sure that the brush is clean and dry.
4. Go to Settings > Sounds (or Settings > Sounds & Haptics), and drag the Ringer and Alerts slider back and forth a few times. If you don't hear any sound, or if your speaker button on the Ringer and Alerts slider is dimmed, your speaker might need service.
5. If you hear sound, try making a call with your iPhone and turn on speakerphone. On iPad or iPod touch, make a FaceTime call. If you still can't hear, or hear static or crackling, then your network or reception could be the issue. Try to call again later, or from a different location."

If the issue remains after completing the steps, contact Apple Support directly to further assist. Get Support

Best.