In firebase cloud function I am using typescript and I am not able to get a solution to convert firestore time stamp human-readable formate currently it is showing as '063720731421.495000000' How to solve this any idea?
A Firestore Timestamp just contains two values (seconds and nanosecond) representing an offset from unix epoch time. This is similar to the Date object that some platforms use to represent a point in time.
The Firestore APIs aren't going to do anything to help you format the date. There are lots of libraries out there for various languages and platforms that will format dates for you. It should be trivial to convert Firestore's Timestamp into something you can pass to one of these libraries. In fact, on many platforms, Timestamp has a method to convert it to a native Date object.
In the JavaScript environment, you can get a Date object by simply calling toDate() on the Timestamp. After that, a library such as moment.js can help you format it any way you want.