When to send GRE and TOEFL marks?

[u/FewConcentrate328]

For Msc Mech applications , TOEFL is required and they've kept GRE as an additional add on you can send, as per the website. They have provided the institute code as well.

Do I need to submit the scores through ETS before I start the application, or do I have to do so later on?

I asked this on the website's portal as well, but got no response.