Old Town Granny Stitch Sweater Pattern + Video Tutorial

Peace, mercy, and blessings of God be upon you. I want to sell digital products, and I want the customer to automatically receive the product file via email or be able to download it directly from here when they pay. However, I've been presented with many options and I don't know which one to choose. Therefore, I need someone to help me because I'm searching on YouTube for a tutorial on this application, but I'm only finding old videos that don't explain the new updates. For this reason, I would appreciate your help and guidance on the correct way to set things up properly and ensure the digital product reaches the customer immediately after the purchase is completed, in an easy and professional manner.