In general PhD students are employees at an academic chair, but they don’t have to be.
For clarification purposes: general agreements are strictly for official use only. Therefore, a fund number is required (so private orders are excluded). In that case the ordered goods are property of the TUM or the academic chair.
To my knowledge software agreements (also LRZ general agreements) are only valid for hardware owned by the TUM or an academic chair (so qualified hardware always carries an inventory label of the TUM). It is prohibited to use the software of these agreements on private hardware, owned by employees or professors. For valid usage of the software-assurance-agreement a windows basic license is also required.
An exception is the Microsoft-Imagine platform, which distributes also personal licenses for eligible users. These licenses can be used on private hardware. If a user can fulfill the requirements for usage of Microsoft Imagine (please read further information on the MS Image website) and has a respective identification/login (LRZ username, i.e. “ga10taf”), he is eligible.