What you want is concatenation, which can be tricky at times. Suggest you research it, but if you put this in a query design grid in the field row, you should get a result with a field name of Test.
Test: "C :\Users\Earl_000\Documents\Pic" & [Case] & "" & [Date] & ".pdf "
If you're in the mood to do more research, check out naming conventions and reserved words. Date is a poor choice for any db name, and the use of brackets as part of a field (Attach(Blank) ) name is not good either.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.