Hi,
Thanks for your questions.
1) We have multiple ways for a user to sign a document. The simplest way is to type your name and EchoSign generates a signature from your name. Another option is to draw your signature using a mouse or finger (from a touch device). The third option is to upload an image of your signature to EchoSign and use it to sign documents. To sign a document all you need is a web browser (you don't need a tablet but the service also works on a tablet).
2) Yes once you create a signature in EchoSign you can sign a document by simply clicking on the electronic signature field.
3) Yes, through the EchoSign UI we have the ability to create signature fields on the document and assign it to specific users.
Let us know if you have additional questions.
Thanks
Mangesh
EchoSign Product Manager