Here's another variation, without written date and a "younger" signature:
Upshot is that Ford pardoned Nixon _without_ specifying any crimes; to the contrary, he rather pointedly addressed the lack of information thereof. So yes, there is precedent for Obama to pardon Hillary without specifying crimes (much less indictment); there's also precedent for Trump to drop the subject on the grounds of wanting to get on with the job of running the country rather than getting bogged down in the mire of rendering justice on scandals past.