All job applications are accepted only through USJobs.Gov now. I was working overseas and was told by email I had 3 days to accept the position or I could decline. So technically I did not even interview for the job. However, that is not the norm, most interviews are done over the phone for initial contact. Even then a manager can hire you outright if your resume is strong and you have hiring points (Vet, Spousal Pref, Disabilty). Most likely they will want to have you come in for a second interview unless it is in a geographically distant place. From my experience, you are more likely to get hired if the job requires relocating. Note: many Government jobs are open to local commute only.