How to upload the data into SAP R/3 System

I have a scenario to upload the flat file data into SAP R/3 System.

I will describe my complete scenario here so that it will be better understanding for you to suggest the solution.

The segments that relevant for the upload of customer master data, namely

HD : Header Segment

PF : Partner Function Segment

OP : Output Segment

TX : Tax Segment

CR : Credit Segment

CT : Customer Text Segment