Do my users see my email id or Let’s Calendar’s email id as sender?

Once you upgrade to “Forever Free” plan, your users will see your name and your email id in the senders info. The Calendar invite they receive and the email they receive as well as the Reply To email id they see, all will reflect your name, email address and domain. They will not see Let’s Calendar anywhere. This happens when you link your own SMTP service and configure a sending identity.