Is it possible to alter documents and attachments once they've been shared with the signatory?

Neither the document nor any attachments can be changed as Signit only sends links to uneditable files.

Where and how do you store data and documents?

We use Amazon to store data. The service is continuously updated with the latest encryption and online security using the latest technologies. You can read more about our data policy and management in the data processor agreement.

How do you ensure that my documents and agreements can't be seen or accessed by anyone besides the selected individuals?

We use digital IDs to ensure that only the selected persons can access the signed documents. In addition, we use AES encryption of all data stored online, and our servers are heavily encrypted and secured by Amazon and Nets.