Below are the regex patterns for some of the values you are trying to retrieve
To retrieve ARUN SUNDARAM, use (?<=BILL TO: ).*?(?= \d+)
To retrieve mail id, use (\w+@\w+.\w+)
Phone number, use \d{10}
Invoice Number, use (?<=INVOICE NUMBER: )\d+
Below are the references to know about IsMatch and Matches activities-