By using Process builder we can create an email activity whenever an email alert is triggered by using ‘Email Message’ Object
Step 1 and 2 :
Choose the source object and define the criteria in this step as shown below,
Define two immdeiate actions, one for Triggering a sample email and other one for an action called ‘Create a Record’ where you need to choose ‘Email Message’ object amd status field is mandatory and value can be chosen upon scenario.
Related To ID in Email message object is like ‘WhatId’, In my scenario i referred Case Id so it will associate Email Activity record to Case object once email is triggered and in ‘To address’ field you should mention related ‘Contact id or lead id’ to make email activity record to get associatted with them.
Results after successful email trigger :
Email activity in case,
Email activity in Contact record,