How do I edit the abstract/title in the metadata form on revision or before publication?

You must edit the abstract (and title, if necessary) not only in the Word document, but also in the online metadata form, when you submit your revision or when you upload your final manuscript version. See How do I edit/correct/enter article metadata before publication? 

This is particularly important if you chose the PubMed Now! option (What is the "PubMed Now!" ("ahead-of-print") option when I pay the APF?), because the abstract and title of the PubMed submission will be generated from our metadata form, not from what is in the manuscript!

As a reminder, a results section in the abstract is also necessary for protocols or proposals, even if there are no results yet (What should I put into the results section of a protocol or proposal?).

Regarding titles, please remember to mention the study design (and "Protocol of a ... Study" for protocols) in the title. See What are JMIR's guidelines for article titles?  

Related:

• How do I edit/correct/enter article metadata before publication? 
• What is the "PubMed Now!" ("ahead-of-print") option when I pay the APF?
• What should I put into the results section of a protocol or proposal?
• What are JMIR's guidelines for article titles?