A well informed census worker has been trying to let people know this fact:
“Just want to get the word out that if you have a PO Box you will NOT get census forms in the mail! We want you all to be counted!”
You can fill out the forms at https://2020census.gov/
When it asks for your ID just go below the box and click on “ I didn’t get an ID” please fill it out.”
The feds did mail out information with ID, but only to physical addresses, no PO Boxes.