There is a lot of programmer in internet you can download pcb and make your own programmer.
Then you need also to download the software which you'll use with the programmer to upload your program inside the PIC. I suggest for you Icprog and winpic.
For the 16F84A µC you should preferably use a GDM-compatible programmer (you can find plenty of schematics and layouts on the net) and the ICProg software.