Around February 2009, the NSA refuses to make a BlackBerry for Clinton that’s secure enough to use in SCIF rooms, citing security concerns. (Highly classified materials can only be read in SCIF rooms, and Clinton’s office in State Department headquarters is a SCIF room.)
According to a September 2016 FBI report, at roughly the same time, Clinton’s executive staff also ask about the possibility of Clinton using an iPad to read her emails in her office. But “this request was also denied due to restrictions associated with the Secretary’s office being in a SCIF.” (Federal Bureau of Investigation, 9/2/2016)
However, the FBI will fail to mention that the iPad won’t actually be announced by Apple until January 2010, and won’t be released until a couple of months after that, making the above claim impossible. (Apple.com, 1/27/2010)
Clinton will buy an iPad and begin using it a couple of months after it comes out, in July 2010.
In FBI Vault Hillary R. Clinton Part 36 of 36 release, the following email was found confirming her use of an iPad after she was officially told she could not use one.