What is considered a process in Taggify App for Shopify store?

One process = one customer or order event checked against your rules. Every time Shopify sends the app a new order, a fulfilled order, a new customer account or a customer account update, the app checks it against your active rules and that counts as one process, whether or not a tag is applied. Tagging past orders does not use processes; it uses the separate past-orders limit of 1000 orders per plan.

Get Taggify app for Shopify store from here Taggify - Customer & Orders