The noun पता means something like “knowledge”. It is used in a variety of common idioms.
पता is used with होना in an indirect verb construction that has the following form:
X को Y पता होना – for X to know Y
A very common phrase is “पता नहीं” (“I don’t know”). This is an elliptical form of the phrase “मुझे पता नहीं है“.
मुझे पता नहीं है कि वह कब आएगा – “I don’t know when he’ll come”
पता is used with चलना in an indirect verb construction that means “to come to know”, “to realize”, etc. It has the following form:
X को Y पता चलना – for X to realize Y
मुझे पता चल गया कि मैं अपना चश्मा लाना भूल गया था – “I realized that I’d forgotten to bring my eyeglasses”
पता is used with करना in a conjunct verb meaning “to find out (i.e, to seek information or knowledge)”.
मैं इन साड़ियों का दाम कैसे पता कर सकती हूं – “How can I find out the price of these saris?”
पता is also used with लगाना to mean “to find out (i.e., to seek information)”.
मैं उसका घर का पता कैसे पता लगा सकता हूं – “How can I find out his home address?”
पता, incidentally, is also a noun that means “address”.