Email Manager Class
public with sharing class EmailManager{
    public static  void sendMail(String [] addresses, String [] subjects, String [] messages) {
        Messaging.SingleEmailMessage [] emails = new Messaging.SingleEmailMessage[]{};
        Integer totalMails = addresses.size();
        for(Integer i=0; i < totalMails; i++){
            Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
            email.setSubject(subjects[i]);
            email.setToAddresses(new List<String> { addresses[i] });
            email.setPlainTextBody(messages[i]);
            emails.add(email);
        }
        Messaging.sendEmail( emails );
    }
}

Trigger :
trigger ExampleTrigger on Contact (after insert,after delete) {

    if(Trigger.isInsert)
    {
        Integer recordCount =Trigger.New.size();
        //Call utility method from another class
       EmailManager.sendMail('nmanoharsfdc@gmail.com','calling Class from trigger','my first task');
    }
    else if(Trigger.isDelete)
    {
        //Process after delete
    }
}

Error : Method does not exist or incorrect signature: void sendMail(String, String, String) from the type EmailManager

I wrote the below code,but througing the error as Constructor not defined and method doesnt exist

//Class
public class ConnectionDetails {
    Private  String  ConnectionCode;
    Private Integer Price;
   //Constructor
    public ConnectionDetails(String ConnectionCode,Integer Price) 
    {
        this.ConnectionCode='ConnectionCode'; 
        this.Price=Price;
    }
  //Method 
    Public static void  showDetails(String ConnectionCode,Integer Price)  
    {
            ConnectionDetails cd =new ConnectionDetails();  
        cd.showDetails('ConnectionCode','Price');       
    } 
    
}

Email Manager Class
public with sharing class EmailManager{
    public static  void sendMail(String [] addresses, String [] subjects, String [] messages) {
        Messaging.SingleEmailMessage [] emails = new Messaging.SingleEmailMessage[]{};
        Integer totalMails = addresses.size();
        for(Integer i=0; i < totalMails; i++){
            Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
            email.setSubject(subjects[i]);
            email.setToAddresses(new List<String> { addresses[i] });
            email.setPlainTextBody(messages[i]);
            emails.add(email);
        }
        Messaging.sendEmail( emails );
    }
}

Trigger :
trigger ExampleTrigger on Contact (after insert,after delete) {

    if(Trigger.isInsert)
    {
        Integer recordCount =Trigger.New.size();
        //Call utility method from another class
       EmailManager.sendMail('nmanoharsfdc@gmail.com','calling Class from trigger','my first task');
    }
    else if(Trigger.isDelete)
    {
        //Process after delete
    }
}

Error : Method does not exist or incorrect signature: void sendMail(String, String, String) from the type EmailManager

I wrote the below code,but througing the error as Constructor not defined and method doesnt exist

//Class
public class ConnectionDetails {
    Private  String  ConnectionCode;
    Private Integer Price;
   //Constructor
    public ConnectionDetails(String ConnectionCode,Integer Price) 
    {
        this.ConnectionCode='ConnectionCode'; 
        this.Price=Price;
    }
  //Method 
    Public static void  showDetails(String ConnectionCode,Integer Price)  
    {
            ConnectionDetails cd =new ConnectionDetails();  
        cd.showDetails('ConnectionCode','Price');       
    } 
    
}