So I'm using Archilogic to get 3D models for a real estate website, but I'm not sure if I have to export it all in order to use it in VR or if I can do it straight from the service?
If I can't use it from the model URL I'm given, can I somehow use it in A-Frame or Three.js?
Archilogic provides native support for Google cardboard. Open your model on your smart phone, turn it into landscape mode, and tap the cardboard icon.
If you wish to use any other VR device, which Archilogic does not yet support, I suggest that you export your model to gltf or obj and then use it within your A-frame application. This way you can easily create 3d content and customize your model in the editor, this does not require any knowledge of a 3d program.
If you have 3d knowledge and you would like to have full control over your 3d data, you should export your scene as a blender file and then go from there.
How to use VR / Google Cardboard
Edit: if you want to export your models, afaik you need to have a subscription. However there is a 30 days trial period - so you could export it using the trials