Zoho syncs once a day, during the night. Any changes made during the day will not automatically reflect in Zoho until the next sync (later that night).
To see new data right away, you can start a manual sync to Zoho under System Settings > System Configuration > General tab. Do not click on edit! Scroll down and click on "Send Data to Zoho Now" to begin the sync.
Refer to the "Upload Finished" field to check when the sync is finished.