The first thing you need to do is read the documentation on fread: http://www.cplusplus.com/reference/cstdio/fread/
] which is pretty clear on what you have to do and even includes an example.
Since you are only allocating a buffer of 100 bytes (and please don't use numbers directly, #define them to a constant so you only set / change them in one place) you cannot read files larger than 100 bytes without using a loop as well. But that is an "exercise for the reader" at this stage.
The parameters to fread are simple:
1) A pointer to the first element of a buffer to receive the data - you have this.
2) The size of the element to be read - you probably don't have this, as you are setting it to the current position of the stream you just opened, and then moved to probably the end of the file...
3) The number of such elements to read - you set this to one.
4) The file stream
But of course, it will read no bytes - because you positioned it at the end of teh file before you started reading it...
Instead, don't seek at all, and use fread to read the size of the buffer:
size_t bytesRead = fread(buffer, 1, 100, rfile);
fwrite(buffer, 1, bytesRead, pFile);
Only use the constant I suggested instead of the number 100.
And check bytesRead - if it is the size of your buffer, then the file isn't finished, so you need to read some more.