I just got a cdi a few weeks ago. You need to get a certificado de domicilio, then get a turno at the afip office for your community. Fill out the from and make a copy along with your passport. Then go to the afip office in person
Could there be any problems with getting a certificate of residence and applying for the CDI while being overstayed on a visa? Such as deportation or fines? I've been overstayed for 6 months.