Prarabdha karma is the part/portion of Sanchita karma that is ready to be experienced in this lifetime. This is the karma that has “ripened”. This can also be called as that identification based on a given context.
For example, a person is a CEO of a company, a father to his/her children, Son/daughter to his/her parents, but does not experience all these roles simultaneously. With children the role of a parent, in the company, a CEO, etc.