hi It sounds like you're experiencing an issue with your iPhone's microphone during phone calls. If the Phone app is not requesting access to the microphone and the microphone icon is not showing up, there are a few things you can try:
1. Check for any physical obstructions: Make sure there's nothing blocking the microphone on your iPhone, such as a case or debris. Sometimes, a simple cleaning or removing any obstructions can help.
2. Restart your iPhone: Give your iPhone a quick restart by turning it off and then back on again. This can help refresh the system and potentially resolve any temporary software glitches.
3. Update your iPhone's software: Check if there are any available software updates for your iPhone. Keeping your device up to date can often fix bugs and improve overall performance.
4. Reset settings: If the issue persists, you can try resetting your iPhone's settings. This won't erase your data, but it will reset your preferences and settings to default. Go to Settings > General > Reset > Reset All Settings.
If this dose not work it time for a repair
https://getsupport.apple.com/products
i hope this helps