If you’d like to automatically create a WordPress user for each CRM contact as they get added, but NOT send them a welcome email, here’s how:
(NOTE: It’s important to follow the steps in order, or all of your current contacts will receive welcome emails after saving the setting in step 2!)
1. In Jetpack CRM > CRM Settings > Mail Templates, open up the “Your Client Portal” template, and then click “Inactive” top right (to set this inactive!)

2. In Jetpack CRM > CRM Settings > Client Portal, make sure “Generate WordPress Users for new contacts” is checked.

… That’s it, your users will now automatically get WordPress accounts created for them, but they won’t get the usual Welcome to the Client Portal email.