Lend can form "lent" in the past, which is useful for talking about when we give somebody something, e.g. "I lent him the money to buy petrol." You can also form phrases such as "I will lend you", or "Do you want me to lend it to you?"
Borrow is for taking something, e.g. "Can I borrow some money for the coffee machine please?" Borrowed is the past form.
Hope this helps