confused about the uni offers/ ucas

Do you only get an offer from a uni after you have met their requirements in the ucas application and have passed the interview (if you're required to)? It feels a bit confusing. I've got an email from university of Greenwich on an invite to book an interview for my foundation pharmacy course but when I checked on the ucas it's still blank on the uni decisions, so I'm just confused how these uni application works.

Hi There!
Most students will receive a conditional offer where the university will say that you have a place under the condition that you get certain grades set by the university.
So, by the end of your A Levels or college course, as long as you achieve the grades set to you by the university, you would have a place.
In terms of courses that interview, it would be dependent on your interview and the grades, so they'd tell you what grades they want you to get in order to go to the university, but you'd also have to pass the interview first.
If you've had an email offering you an interview, I'd suggest to book onto it because UCAS might not have updated yet, or they might be waiting to update UCAS until they see whether or not you have been successful in your interview.
I hope this helps,
From Josh
Official LJMU Student Rep

For courses that interview they’ll do the interview first then make a decision (either an offer or unsuccessful).
Offers can be conditional but conditions will normally be for qualifications/grades not for non academic conditions