Hi @MB
We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a real picture as your avatar because it helps build community!
We support functions like pulldata/search which read data from external csv files attached to your form.
If those csv files are dynamic and you need to update them then you need to upload a new version to your server (ODK Central for example) and redownload in Collect. To make sure it's always updated in Collect you can enable Exactly match server
If you need to know more about those functions: