eForm has built in support for mapping submissions to registered users. If a logged in user submits any of the eForm managed forms, then the submission automatically stores the account information. To access it from the backend, please follow the steps.
It will show submissions made by the selected user. Now you can perform all sort of administrative actions on them.
Also, when user is not logged in, or when you have disabled logging registered users from a form, then the user field would show Guest. You can also select Guest from the dropdown to list all unknown users.
eForm gives a beautiful interface to users for accessing their previous submissions. To make use of it, you do need to setup the required pages. You can either do it manually or follow the wizard.