使用预准备语句检查数据库中是否已有电子邮件

I am trying to change my code to msqli prepared statements from mysql. I am not sure how to adapt my code that currently works to check if there is an email already in the database. Below is the code I am currently using that works. How do I change this into a prepared statement and get the same result?I am trying to change my code to msqli prepared