What are the different methods of batch Apex class in Salesforce?

There are three methods in Batch Apex.

1. Start: This method is called at the very beginning and it is used to collect the records through query or objects to be passed to the execute method.
   Syntax: global (Database.QueryLocator | Iterable<sObject>) start(Database.BatchableContext bc) {}
2. Execute: We use this method to do required processing for every chunk of data.
   Syntax: global void execute(Database.BatchableContext BC, list<ListOfRecords>){}
3.  Finish: This method is executed after all the batches are processed. We can use this method to send email confirmations or execute post processing operations.
   Syntax: global void finish(Database.BatchableContext BC){}