Hey I would like to know to step to getting my battery replaced

Start by checking your battery's maximum capacity here:

Settings → Battery → Battery Health & Charging → See Maximum Capacity

If it is around 80% then you should change your battery. Apple also recommends replacing the battery at around 80%

You can find more information, as well as local prices for battery replacement here:

iPhone Battery Repair & Replacement - Apple Support

Go to this web site for information about how to request battery service for your iPhone: iPhone Battery Repair & Replacement - Apple Support

For cost and availability, enter your model information in the "Get an estimate" box at the bottom. (I will let you do this since the answer will depend upon the country where you are located.)

Is it really time to change your battery? See this excerpt from: Batteries - Maximizing Performance - Apple

"A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge."

Look here -

iPhone Battery Repair & Replacement - Apple Support

Get an appointment at an Apple Store or Apple authorized service center for an evaluation of your phone and battery replacement as needed. What is the current battery health level?