im new in manager
can I delete some of the fields in customer form
No. But you can leave any of them except the customer name blank. Some fields do not appear unless certain tabs are enabled. If you are not using those tabs, disable them and the related fields will disappear. See Enter customers | Manager.
Understand that if information is omitted, certain Manager functions will not work, such as emailing transactions to customers if the email address is left blank.
Thank you very much