DPD is that yellow form, that we used to get to fill in on return to Aust, papery card board sort of thing.
Easy to fill in, as we know what to write.
There used to be the green OPC, but that one is no longer used.
The yellow form, or IPC, is the one you fill in on the plane, at your leisure, with a biro/pen.
You can fill it out before too, as you could have taken some when you come in previous trips.
Now, its all app or webform, so you will need either a mobile phone, or laptop, or computer where you can fill in data, and take photo of passport data page and selfie.
Quite onerous.
If you don't have a smartphone, you will need a laptop or computer, which is secure, ie, not a public one where there might be keyloggers on it.
Last one from me on this, really, it puts a dampner on int trips.
Bring a laptop, and international charger, and 7 days before trip back to Aust, you can fill in a few things, but 72 hours before trip back, you have to lodge the DPD electronically, for every pax.
Youtube has some videos on how to do it, some on here way its easy, some say complicated.
And no, I haven't filled one in, yet.
Have to create an account, and put in password, too.
Ie, more data for them to know about us.