Hello oneforbiz,
Thanks for that info and for choosing the Apple Support Communities. If we understand correctly, you are unable to find your Mail app on your iPhone. First, make sure your iPhone is up to date, as the updates contain stability fixes that can resolve issues like yours, as well as important security updates to keep your iPhone safe.
Update the iOS software on your iPhone, iPad, or iPod touch
If you are still not able to find the Mail app, see if resetting the Home Screen layout helps your situation by going to Settings > General > Reset > Reset Home Screen Layout and here is more info:
Return iPhone settings to their defaults
Cheers!