We need to send email for a specific request using its corresponding email template and shown in the screenshot below.
So which Salesforce lightning activity or API can we use to send email for request?
And which parameter in the activity can be used to attach corresponding email template?
The screenshot which you posted is ?
That is how it will be done in Salesforce lightning UI. I found it in google which is similar to my question.
Email in Salesforce is not easy stuff. I have here a video with an example of sending an email: