I hope she is: because it´s the way it is. It´s accepted usage that if you say something that is true at a future time (with a certain degree of certainty or probability) you will use the verb in it´s pure (infinitive) form:
I hope she is pregnant. (eu espero que ela esteja grávida.)
When the user is ready to send, he/she simply connects and uploads the document.
(Quando o usuário estiver pronto para enviar, deve simplesmente se conectar e fazer o upload do documento.)
As you see, at the moment of the statement, we don´t think of the other option.