A call summary is the written record of a call that someone else took for you: who rang, the number they rang from, when, and what they wanted, in a line or two. It is what a good receptionist leaves on the pad by the phone and what an answering service sends after each call. A summary is not a transcript. Its job is to let you act on the call in thirty seconds without ringing the person back to ask what they meant.
A good summary answers three questions: who is this, what do they want, and what do I need to do. "Jess, a regular, wants to move her Thursday lash fill to next week, any afternoon, and left her mobile" is a summary. "Client called about appointment" is not.
In practice
A day spa with no receptionist on Mondays gets 14 calls that day. Read as summaries, they sort quickly: 8 booking requests, 3 voucher questions, 2 cancellations and 1 supplier. The owner replies to the 8 requests and the 2 cancellations first, because those decide who is in the rooms this week, and leaves the supplier until Friday. Without summaries she would be listening to voicemails, or more likely ringing back numbers she does not recognise.
Keep summaries for a while. When a client says they cancelled with plenty of notice, the time on the summary settles the question kindly.
In Glow Line
Every answered call ends with a text to your mobile: a booking request with the name, service, preferred time and mobile, or a short summary of the message. The Bookings page also lists recent calls with the number, the time and a one-line summary. See call summaries.