Adobe Media Encoder places exported files in the same folder as the source videoclip.
To choose a different destination, you can do one of the following.
If you want a single item to go to a different destination, simply click on the name and browse to the folder you want the encoded file to be placed.
If you want multiple items in the queue to go to a different destination, select these items by dragging a selection rectangle from an empty spot at the bottom of the queue or by selecting the first one and holding down the Shift key when clicking on the last one.
With the desired items selected, click on one of the output file names.
This brings up a dialog where you can browse to the new output folder.
A more permanent alternative is to set the fixed destination folder as a preference.
Go to Preferences... in the Menu bar, in Windows, you'll find it under Edit, in the General section, under Output, you can check "Specify output file destination", and then browse to the desired folder on your system.
Note that this will have no effect on items already in the queue, but rather effects newly added clips.
