With GrubHub you can order food online. But when you’re not planning to order online anymore, you might of course be considering to close your account. In that case: I can tell you that all it takes, is 1 email to their support email addres.
I’ll show you below the one single email you need to send to remove your profile from their website and their reply (with screenshots):
1 Write an email to firstname.lastname@example.org
Your e-mail could be looking like this:
Subject: Request to delete my account & personal data
Source (& thanks to): grubhub.com