If you have students who require additional time on exams/assignments as an accommodation, you are easily able to set this up in Gradescope.

Select the exam or assignment which you wish to modify, then select "Extensions" from the left menu bar. (Note: This option only appears in exams or assignments for which you have set a time limit. If you would like to go back and add a time limit to an existing exam/assignment, you can do that from the assignment settings.)

You will be taken to a new page displaying existing extensions for this assignment. Select "Add an extension." (If you already have existing extensions for this assignment, scroll to the bottom to find the button to add a new extension.)

Search by name or email for the students in your course who require the extension.

Check the box "Maximum Time Permitted." You can either enter a multiplier for the time limit (i.e. the students will receive 1.5x or 2x the standard time) or input a specific amount of extra minutes the students will receive. 

Select "Add Extension." All of your extensions for this exam/quiz will now be displayed under the "Extensions" tab.