Where is the Actual Location to Measure the Current into Drive?

Your question is not clear. Normally Ampere meters are installed at the motor control panels. A clip on ammeter (tong tester) can measure the current at any point from substation to the motor terminal depending up on the requirement. It is always better to study the basic concepts and understand the basics before putting up your question. For the second part of the question it is basic electrical theory and need to be learnt before practicing electrical engineering.