If you manage to locate a PDF version of the script, you will quickly realize there are two distinct versions floating around, and the "portable" file often conflates them.
When searching for a PDF portable version of the script: an american in paris musical script pdf portable
If you are part of a theater group considering a production, you can often request a digital perusal script through their official portal. If you manage to locate a PDF version
For the official 2015 stage musical script (book by Craig Lucas), digital versions are restricted due to licensing. an american in paris musical script pdf portable