Approval requests are generated along with the generation of weekly timesheet reports, which are generated and sent to users every week at 9 AM on Saturdays in their timezone. Once the user clicks the Verify and submit timesheet for approval button in the email they receive, the approvers (the managers of the projects under which the user has added time entries for that week) will be notified about the request by email.
If a user adds a new time entry after the generation of approval requests, that is, after 9 AM on Saturday, they will have to go to the Weekly timesheet reports page and click the Resubmit for approval button under the triple-dot menu in the Actions column of the corresponding week. This is important since the approvers will get the updated time entries in the approval request only if this is done.