By accessing your built-in controls, you can adjust your hearing aid programs, volume, as well as any wireless accessories you may have paired to your hearing aids.
You have two options to access your functionality.
Triple click the side button on your phone to bring up the following screen (iPhone X or newer) or use the home button (iPhone 8 or older).
Here you will have the option to adjust microphone level (surrounding sound), adjust Treble and Bass level (depending on hearing aid model), as well as additional program adjustments.
By selecting Presets, you will be able to change programs.
These programs were set by your hearing care professional.
Alternatively, you may access these features through your Control Center. This is accessible through either a downward swipe from the upper right corner (on the iPhone X and newer) or from the bottom up (on the iPhone 8 and older) as shown.
After you swipe, the Control Center will be visible. Select the Ear icon on the screen.
If the Ear icon is not visible, go to settings, control center and click the + next to Hearing. Then try swiping again and it should be visible.
Once selected, the built-in accessibility functionality will be available.