Please increase my battery health

That's not possible. Battery health is a function of usage and chemical aging. The more you use a battery the less health it will have and themes power it will be able to store due to the chemical aging processes within the battery.

There is no way to increase battery health other than entirely replacing the battery once it gets below 80%.

See here to set up an appointment at an Apple Store or Authorized service provider to get your battery replaced: click here-> iPhone Battery Replacement - Official Apple Support