How to upload folder on Anvil Form

I recommend the following links:
From Anvil’s Docs (the Uplink: Code outside Anvil section):
Connecting to Data Tables
Tutorial: Using the Uplink

These are things you could have readily found for yourself, using the links at the top of the page. I encourage you to use them, especially the Search feature. You can often find answers for yourself in a fraction of the time.