You could add a date field on the user who signed up called “Confirmed Date” and have a workflow where if there is not a confirmed date it takes the user to a page that just has a general “We will get back to you shortly”.
Then send yourself an email with a confirm button/link. The link could be to a hidden page on your app that also had a URL parameter holding the person who signed up unique id.
Ex: bubbleapp/secretpage?uid=[person’s unique id]
I would on the page then have a workflow that says if page is loaded and current user is you (or signed in or role=admin) then:
Make changes to thing – get unique id from url parameter to find the user and make the confirmed date = current date/time
I guess technically you don’t have to have a secret page, you could do this on your main page if you wanted. I’d just make sure you have some sort of privacy rule and/or conditional that says only you can confirm a user.
This is just one way you could do it. I’m sure there are other ways as well. Hope this helps!
Complementing @Eighty20Software great advice another way could be to simply establish conditionality that restricts the user from accessing any page in your app. Place it on the header so that it applies anywhere the unapproved user attempts to navigate to. You could even have logic that opens a popup informing him/her that his application is under review.
As for what conditions you can use …. Take your pick:
Yes/no
Empty field for whatever you use … a date? a role?