you don't post it. your school does.
Once you are down typing the schools that you attended on AMCAS, there's a little menu bar on the left hand saying 'TRANSCRIPT REQUESTS." click on that...and it should take you to a screen where your school list comes up which you attneded. For example, I have 3. So, you click on one of those school names, and it takes you to a screen where you get to choose if you want AMCAS to get a copy, or yourself, or both. You pick the appropriate boxes, make sure the addresses are correct, and eventually it will take you to a screen called "PRINT TRANSCRIPT REQUESTS." Click on that, and print as many as you want for youreslf.
You make one copy of that, and take it to your school registrar who will (usually for a small fee) take that form, process it, and send it in to AMCAS. When you talk to your registrar, MAKE SURE you remind them that the AMCAS printed transcript request has to go with the transcript. MAKE SURE!!! The transcripts have to be OFFICIAL..i.e. you can't post them, your school has to do it confidentially. You can also get an extra copy of transcripts for yourself, to use when adding courses into AMCAS.
Hope this helps.
Tweetie