In cases where you have emails in your Inbox, that you would like to convert to tickets in Freshservice, you could forward those emails to your support email address. As such, this would create a ticket with you as the requester of the ticket. However, you could create a ticket with the original sender as the requester, when an email is forwarded from your mailbox to the support email address.

To set this up, please navigate to the Admin -->Channels --> Email --> Email settings and Mailboxes --> Turn ON the option "For forwarded emails, use original sender as requester". After this option is turned on, tickets created through forwarded emails would use the original sender of the email as the requester of the ticket instead of the agent who is forwarding the email.