how do you find the health app

from your Home Screen, swipe left until you get to the App Library.

swipe downward and you should get an alphabetical list of all your apps.

scroll to Health or type it in the search field.

If you want it back out to your Home Screen, then tap/hold until it highlights/lifts then drag it

sure, review this support article

How to move apps and create folders on your iPhone, iPad, or iPod touch - Apple Support

basically you'll tap and hold on the Health app, a menu will pop up, select Edit Home Screen and all the apps/widgets will start wiggling. At this point you can tap and drag the app, if you want to get to a different Home Screen, pull it against the far left side of the current screen and it'll index to the previous screen.

It'll probably take a little practice. If you drag it onto a screen that is already full, it will rearrange the apps and make room..