How to add your symptoms to the Health app in iOS 13.6
The newly released iOS 13.6 software update brings quite a few new features to iPhone, including a new Health symptoms tracker. Here's how to use it.

Apple updates iPhone to iOS 13.6
An important aspect of tracking your health is constant monitoring of symptoms and other important metrics. The Health app has long excelled at tracking measurable metrics such as steps, weight and hours of sleep. It even captured any diagnosed conditions, but symptoms weren't specifically included.
Now, with iOS 13.6, there is a new "symptoms" category within the Health app. Here's how Apple describes it:

New symptom tracking in the iOS 13.6 Health app
Apple just released iOS and iPadOS 13.6 to the public with new Apple News+ audio, daily briefings, and more local coverage.

Apple updates iPhone to iOS 13.6
An important aspect of tracking your health is constant monitoring of symptoms and other important metrics. The Health app has long excelled at tracking measurable metrics such as steps, weight and hours of sleep. It even captured any diagnosed conditions, but symptoms weren't specifically included.
Now, with iOS 13.6, there is a new "symptoms" category within the Health app. Here's how Apple describes it:
Inside this new category are 39 different symptoms that users are able to add and track. Without listing all 39, nearly any symptom you can imagine is included. There are options for nausea, runny nose, sleep changes, fatigue, dry skin, coughing, and more."Ability to log new symptoms, like fever, chills, sore throat or coughing, and share them with third-party apps"

New symptom tracking in the iOS 13.6 Health app
To add a symptom
- Open the Health app
- Tap Browse
- Either search for your symptom, or scroll down to the "symptom" category and browse the available options
- Tap Add Data in the top-right corner and choose the level of your symptom
Apple just released iOS and iPadOS 13.6 to the public with new Apple News+ audio, daily briefings, and more local coverage.
Comments
Weird. First off, the reasons for tracking symptoms are pretty obvious — to be able to better communicate those to your health professional. Which leads us to your second question — the third party app is your health provider's, for example I just added Kaiser Permanente to my Health app to access data from. Your data is encrypted and you have control over whether you share your data with other apps or not, or simply bring it to your doctor to show your data in person. "Gimmicky" is pretty much the opposite of what this is.