Mosiah sends a written word. Although modern readers easily see a leaflet or flier with the information that each person might read, that would have been unusual in the ancient world. Although Nephite society clearly had those who could read and write, it is quite likely that those talents were restricted to a few members of the society. What likely happened was similar to what occurred in the Old World. The written word would be taken by a person who could read, and it would be read out loud to the various groups.
We have seen the people of Zarahemla divided into at least two large groups, which likely represented descendants of Nephi and of Zarahemla (who were ultimately descendants of Mulek). However, inside those divisions it is probable that there were also tribal divisions, or at least great families, where those who were of a similar descent would live in general proximity to others. It is therefore likely that this proclamation was read to these large family groups.
The import of the message is that King Mosiah understood that the lack of a designated heir could lead to “shedding much blood and perverting the way of the Lord.” Therefore, he will propose an innovative solution.