Email accounts can send or receive emails (with attachments) no larger than 50mb.
If you need to email a larger file, we highly suggest you uploading the file to your disk space (using either the File Manager in the cPanel or a FTP program) and linking to the file and emailing a link to that file or files.
NOTE: many email providers have a much lower limit of what the receiving email accounts can receive. Gmail for example has a 25mb limit. If you have email forwarding from your @example.com email address to an email provider with a lower limit, emails with an attachment larger than the lower limit can not be sent.