The engagement ceremony process in the Wizarding World is very simple.
Many ordinary families do not even hold engagement banquets, often just setting the wedding date verbally and leaving it at that.
For top-tier pure-blood families like the Malfoy family, when Lucius and Narcissa got engaged, the heads of both families simply hosted a small gathering, inviting a few close family heads from their social circle to publicly announce the engagement of the two children.
Chapter 379