Getting permission to pull a credit report

We are reviewing our procedures when it comes to pulling credit for loans/credit cards. One question that has come up is - what is required when pulling credit? Our branch staff can take in-person and telephone applications. For in-person applications should we have the customer sign a document stating that they are authorizing us to pull credit? What should that process look like for applications taken over the phone? We are concerned that if we add a check box to the application the branch employee may click that box without discussing with the client (for both in person and over the phone applications).