Fill it in through the pdf - it's far easier - don't print it off and fill it in by hand, only print it when you (the US citizen) are ready to sign.
Surnames should be in CAPITALS.
Don't leave blanks - fill them with either 'none' or 'n/a'.
You probably won't have an Alien Registration Number yet - don't sweat it, just put "none".
Finally...
If one of you is abroad and the other is in the US then question C-22 is a bit of a puzzler:
22. Complete the information below if your relative is in the United States and will apply for adjustment of status.As the questions begins by asking you to complete it if the relative is in the US you may think you should just ignore that - However, the section beginning "If your relative is not eligible for adjustment" shows that this is just a badly worded "or" question.
Your relative is in the United States
and will apply for adjustment of status
to that of a lawful permanent resident
at the USCIS office in:If your relative is not eligible for adjustment
of status, he or she will apply for a visa
abroad at the American consular post in:
(City)_____ (State)______ (City)_______ (Country)________
NOTE: Designation of a U.S. embassy or consulate outside the country of your relative's last residence does not guarantee acceptance for processing by that post. Acceptance is at the discretion of the designated embassy or consulate.
We went for:
(City) N/A (State) N/A (City) London (Country) England, UK
(We'll let you know how it turns out...)
