Below are various forms that will open using Adobe Acrobat (pdf files). Some you can fill out right on your computer, others you will have to print out and fill in by hand. Most forms ask for your signature.
Federal Post Card Application (FPCA)
Service members, their eligible family members and overseas citizens can use the FPCA to both register to vote and request their absentee ballots. FVAP.gov offers an FPCA online assistant that guides users through the form-completion process, as well as, a fillable PDF form of the FPCA for download.