When a blue microphone icon appears in the iPhone status bar, it means that Voice Control is enabled. If your iPhone seems to be permanently in dictation mode, and the blue mic icon shows up in the iOS status bar your device is waiting for Voice Control commands.
Phone Noise Cancellation can be found under Settings -> Accessibility -> Audio/Visual.
There's only one catch, Apple has discontinued this feature on the iPhone 13 and later. If your previous iPhone supported Noise Cancellation during phone calls, the toggle to activate it has been removed.
Apple has added more features to the accessibility settings on iPhone and iPad. Now users can customize settings for individual apps. Each app has its own design and functionality, which could mean things are more difficult to use. iOS can be configured to apply custom settings such as larger text or increased contrast to a particular app. Once set, these settings will only affect the chosen app.
Per-app settings can be configured for any number of apps, without changing any settings elsewhere.
There have been Accessibility options to change the appearance of your iPhone apps for some time now. For instance you can change the font size, use bold text, change contrast and so on. Any changes you make, however, are system wide and will affect all of your apps. Not so in iOS 15 - now you can change the appearance of apps on a per-app basis. Here's how to do it on iPhone:
Ambient noise, white noise, dark noise; whatever you want to call it, the App Store abounds with apps dedicated to playing background noise to help you focus, find calm, fall asleep, tap into your subconscious and so on. Apple has taken note of the general enthusiasm regarding such apps and has added its own background noise feature in iOS 15 - Background Sounds. It isn't a stand alone app, rather it is an Accessibility feature that you can use to drown out distracting noise in your environment, help you meditate, help you sleep and so on.