A management system has to say what will be communicated, to whom, and by what means. The communications register is that plan, so a later audit or review can use a record rather than reconstruct it from email.
What the plan shows
Each communication has an audience and a way of being sent. Type, timing, and mechanism come from lists the organisation maintains, so the same words are used across the register. Status shows whether it is still being drafted, still in use, or retired. When approval is required, the record can name who approved it.
The counts show how many communications are on the register, how many are internal, how many are external, and how many need approval. A control test can keep an image of the register as evidence of what was planned.
When you need to change it
The communications register and communications configuration describe the row and the lists it uses.