To affix a legal e-signature on an uploaded 3rd party document, open the contract and click the "add signature field" icon:
Then simply click to place the signature field in the document where you want to sign:
If you need to add some additional fields to prepare the signature block such as date or position title, use "add variable field" icon:
Click to place and fill additional fields in the text as needed:
If the deal still needs to be signed by the other party, export the deal to send for countersignature. When you receive the countersigned copy, you can upload the mutually executed document as the latest version of your document history.
Update Contract Status
Once the deal is mutually executed, adjust deal status to "Done" using the drop down menu at upper left: