Hi,

When you are designing your K2 workflow, if you used a SmartForms Client Event, there should be an Action Display Settings, where you can specify how you want the actions to be displayed on the form.

To perform additional function after your user approved a form, you cannot let K2 add the action panel for you. Instead, you have use the other two options, which is:

1) Use an existing list control to display the action

2) Configure how the actions display later using K2 Designer

From there, you can just insert additional rules after your user perform the action to approve the form. K2 should support DocuSign intergration, so you can look into that for electronic signatures.

If you want something simpler, you can create a simple view, with some disclaimer and a button for user to click to 'sign' the form. On that button click rule, just add the rule you want, for instance, trigger a SmartObject to record the user's username in some SQL table. So when user approve the form, before the form is actually approved, you can show that view as a subview, then once user click on that button, the form will get approved, and then store the username somewhere. 

I don't think you can use the user's password as a signature, as there should not be any way for K2 to retrieve and display password from AD.