How to send email in TriggerClass in Salesforce

TriggerClass .java

Rectypeid = Schema.SObjectType.Your_Object_API_Name.getRecordTypeInfosByName().get('Record Type').getRecordTypeId();
List<Your_Object_API_Name> terms= [select ownerId,Email__c from Your_Object_API_Name where id in: SID]; // SID :set ID
List <String> ToAddresses = new List <String>();  
ID ownerid; // Get Owner ID
boolean Emailexist=false;
for(Your_Object_API_Name poi:terms){
    if(poi.Email__c!=null){
        ToAddresses.add(poi.Email__c); // Get Email address of Supplier
        ownerid=poi.ownerId;
        Emailexist=true;
    }
}
Id templateId;// ID userid = UserInfo.getUserId();
String templateApiName = 'Email template  Name';     //  Set Email template          
try {
    templateId = [select id, name from EmailTemplate where developername = : templateApiName].id;
}catch (Exception e) {
    //throw new UtilException ('[U-03] Unable to locate EmailTemplate using name: ' + templateApiName + ' refer to Setup | Communications Templates ' + templateApiName);
}//User currentUser = [SELECT Id, Email FROM User WHERE Id =:userid]; // Get User Id
for(id rid : SID){
    if( Emailexist==true){
        Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage(); 
        email.setTargetObjectId(ownerid);
        email.setToAddresses( ToAddresses );
        email.setWhatId(rid );
        email.setSaveAsActivity(false); 
        email.setBccSender(false);
        email.setUseSignature(false);
        email.setTemplateId(templateId);
        Messaging.SendEmailResult [] r = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
    }
    
}