Can I pass in the folder name where I want to save the file, on the bucket

[gauravbluepi]

In you example you have used Meteor Username to create the foldername, but can I pass in my own folder name where I want to store the file.

[gsuess]

You can return any string in the .key() function. This string is basically the file-name under which the file is going to be stored in the bucket. So yes, you can use any folder name.