To change the "Display Name" associated with your Klenty emails, head to:
Settings > Email settings > Email account > Display Name > give a display name.
Do not forget to hit the tick after updating the display name. Also note, display name can be changed only for Gmail & SMTP/IMAP connections.
Users who are connected to the outlook domain have to make changes of the display name directly in the Outlook account, which will be reflected in Klenty.