If you already have a paid Dropbox Sign account your company would need to have a Dropbox Sign Enterprise plan with Salesforce enabled. This plan is available by contacting Dropbox Sign Sales.
Already have a free Dropbox Sign account? If you have a Free Dropbox Sign account you can install Dropbox Sign for Salesforce and when you connect, you'll automatically be enrolled in our free, 30-day Dropbox Sign for Salesforce Trial.
Don't have a Dropbox Sign account? You can still try out Dropbox Sign for Salesforce for free! Just create a new Dropbox Sign account for free at sign.dropbox.com, and confirm your account via the email we will send. Once that's done, just install and connect as detailed in our Admin Guide, which includes full instructions on installation and functionality.