Use Upload All to batch-upload grades and feedback that you've created outside of the site or offline. See How do I download assignments for grading offline? for information about downloading files for offline grading.
If you have previously extracted the zip file on your computer, and then edited or added to the assignment grades or feedback, create a new archive or zip file for upload that includes your changes.
Create a zip file from a folder in Windows by right-clicking on the folder, and then selecting Send to and Compressed (zipped) folder. The zip file will have the same name as the folder you selected.
Tip: You can either compress/zip all existing assignment folders at once for upload, or just one assignment folder at a time.
Select the Assignments tool from the Tool Menu of your site.
Click Choose File to browse for and select the archive file on your local computer..
Note: The archive file must contain a folder for the assignment and subfolders for each of the individual students. To ensure that your file is in the correct format, download the assignment submissions (or the template provided) directly from the Assignments tool in your site.
Click the Upload button to upload your file.