Yes, the IRB provides templates for both requesting site permission and for the site to use to grant permission.  Note that these templates are to guide you in preparing the request and to provide to the site an example of what the permission letter should look like. They are not intended to be downloaded and filled out. 

Most importantly, the site permission letter must be printed on site letterhead and hand-signed by the appropriate signatory. Additionally, the letter must be dated within 6 months of IRB submission and detail what activities the site allows the research conduct.