Suppose "Supplier" is the record type name in Account object
Then the query to retrieve accounts of this recordtype is
list<Account> accountList =[select id,name,recordtypeId from Account where recordType.name=:'Supplier'];
system.debug('accountListaccountList'+accountList );
Then the query to retrieve accounts of this recordtype is
list<Account> accountList =[select id,name,recordtypeId from Account where recordType.name=:'Supplier'];
system.debug('accountListaccountList'+accountList );