Adetailed list of questions submitted to external vendors to determine how well they meet the organization's specific requirements is called:

It is called Request for Proposal/RFP. It a report that requests proposition, frequently made through an offering procedure, by an office or organization inspired by obtainment of a ware, administration, or important resource, to potential providers to submit business recommendations. 
A RFP is utilized where the demand requires specialized aptitude, particular capacity, or where the item or administration being asked for does not yet exist, and the proposition may require innovative work to make whatever is being asked.