When you email a client from Gmail, Outlook or your phone, add your BCC address in Bcc. The email lands on that client's timeline, so their history is in one place.
Setup › Log your emails to clients has your address with a Copy button, and where to put it in Gmail, Outlook and iPhone Mail. The step ticks itself when your first email lands on a client's timeline.
It works with any mailbox. FOLLOWap keeps a short snippet of each email, not the whole message.