How do I get documents that are missing from my iPERMS/OMPF (e.g. 1st deployment, ERB, etc.)?

Do you have the documents? If you have the hard copies or digital copies, you go talk to S1 to update your files. If you don't have any copies of them and you can't get them from the unit you were in when you were given them, then you're SOL.

Are you asking how to upload documents to fill gaps in your OMPF with hard copies you have on hand? Or are you asking where you can get documentation that doesn't exist in your OMPF?

You can upload directly to the site. It will be reviewed and updated by HRC personnel.