User Activity

Is there a way to mass send invoices? We have about 30 jobs per day and need to send out all invoices at once. This one at a time is not efficient for us.
We are trying to send all of our customers a new Annual Service Letter. Basically it signs them up for our Annual Services which translates as a Membership in Service Titan. I am wondering if there is a way through Service Titan to track who has been...