Customizing invitations/expiring invitations

For those clients requesting invitations via email, I have found some have email refresh frequency settings that do not allow for real time invitations as with texting. This tends to chew up a lot of each visit, and I’ve learned to dread these.

Is it possible to send an email invitation to a client with a custom message such as “Our appointment will be at 11 a.m., which is about 60 minutes away, and I look forward to seeing you then” or similar?

Similarly, I’ve had clients access the link literally 8 hours later, so it might be helpful to have links expire after the set visit time, and let them know that it expired without sending a separate message by another means.