Federal Post Card Application (FPCA)
There is no witness or notary requirement for the FPCA. A witness may only be required if a voter receives assistance when completing the form.
Federal Write-in Absentee Ballot (FWAB)
There is no notary requirement for the FWAB, but a few states do have witnessing requirements. You can find out if your state has witnessnessing requirements for the FWAB on The Federal Assistance Voting Program (FVAP) website.