Log in to MyAccount at accounts.globe.com.ph
From the Account List page, select your Postpaid account and then click on the "Manage Account" button.
That takes you to your Account Dashboard. Click the "Send MMS/Data Settings" button in the "I WANT TO…" section of the page.
A pop-up will teach you on how to configure your phone's MMS/Data Settings. Simply follow the on-screen instructions and you're good to go!