Formerly, proposals have to be created offline and the uploaded to the system during proposal submission. This facility is still available.
Now, a WYSIWYG editor that brings to the web much of the power of desktop editors like MS Word has been integrated into OPM.
You can now type in your entire proposal online.
Subsequently, you can save the proposal as an RTF file to your desktop or laptop. You can then edit it in MS Word, for example; and import it back to your proposal form in OPM.
Uploading of Supporting Documents, in whatever format, is still supported.