How to Convert Emails to Tasks or Event or Calls

Hi

I just found out that bcc, outlook plugin and imap all don't keep the emails in zoho crm if I i delete them from the email system. I need it to keep email system size small. How can I automatically convert the emails in zoho crm into tasks or events or calls. I figured this will keep the emails in the system even if I delete them from my email company. Does anyone know how to convert emails into tasks, events, calls, cases anything to keep it in the crm system. Thanks!