Depending on their purpose, there are several methods of attaching files.
Clients: For the fastest & easiest experience, we highly recommend using our DropBox sharing option whenever possible.
Requesting Estimates (all)
Number of files allowed: 1
Maximum files size: 2MB
File attachments allowed: .jpg, .png, .pdf, .doc, .xlsx
If more files are needed to help clarifications, we will let you know in our response.
Tickets (all)
Number of files allowed: 2
Maximum files size: 2MB each
File attachments allowed: .jpg, .png, .pdf, .doc, .xlsx
If more files are needed to help clarifications, we will let you know in our response.
Projects
- Must be logged into verified account.
Number of files allowed: unlimited
Maximum files size: 2MB each
File attachments allowed: .jpg, .png, .pdf, .doc, .xlsx
DropBox Sharing (recommended)
- Must be logged into verified account.
Number of files allowed: unlimited
Maximum files size: unlimited
File attachments allowed: unlimited
Save a TON of time by using our DropBox file sharing. Store and organize all your files in your own DropBox account, and simply check the boxes of files you’d like to attach to Projects, Discussions, Tasks and more.
To use this option: you will need to allow a "handshake" between DropBox and 3Polars. You'll only need to do this once, but you can easily disconnect and re-connect this handshake any time.
1) The first time you use this option, look for the button shown below: 
2) Clicking the button will bring up a DropBox login window.
3) Then, to attach files to Tasks, Projects, Discussions, etc (anytime you see that button), you can check the box next to the file on your DropBox.
(note: The files won't actually upload, they are being "tagged" to your Project)