You can use the Request a File link in the navigation bar. This will look very similar to setting up an email.
By default, files uploaded through a Request will be uploaded to your File Box. Remember, files that are in the File Box for more than 30 days will automatically be deleted by the system.
Note: If you would prefer to have the files uploaded using the links sent to a created folder on your account, you can click on the File Box icon listed as the 'Upload Location' on the Request form to select a different destination folder.
To have files uploaded directly to a folder through a request, use the Request Files link located on the right menu within a folder.
What your client will see:
The recipient will receive an email which includes a link. When they click on the link they will be brought to page that will allow them to upload a file into your account.
More information on how to send large files