"Personal letterhead" example?

I'm currently working full-time in a government agency. I'm providing a letter of recommendation for a student who worked with me, as they are applying to an academic program.

The program requires rec letters to be on letterhead. I wrote the department informing them that my agency does not permit use of official letterhead for this type of correspondence. They responded that I can use "personal letterhead". I may ask them to elaborate, but unsure if they will respond in a timely manner.

Does anyone have an example of what "personal letterhead" might look like? Would I just put my contact information in the header of a Word doc?