When to have a headstone unveiling
A headstone unveiling should take place within a year of the death. Many families choose to have the unveiling around the one-year anniversary, though a headstone unveiling may be held at any time in the first year. Some families also choose to have an unveiling immediately after shiva , and some choose to have an unveiling after the 30-day mourning period known as "shloshim ."
Headstone unveiling ceremony
Before the ceremony begins, the headstone is covered in a sheet or cloth. The family can place the cloth on the headstone, or the cemetery staff may be able to coordinate this. Those in attendance gather around the headstone and recite psalms and perhaps a brief eulogy  before removing the cloth. The Memorial Prayer, called “El Maleh Rachamim,” is recited. If there are at least ten people in attendance (known as a "minyan"), the Mourner’s Blessing, called “Mourner’s Kaddish,” may be recited.
After the prayers have been recited, those in attendance will place small stones on the headstone as a sign that they visited the grave and as a sign of respect for the person who died.
Who should lead the unveiling ceremony?
It is common to engage a rabbi to lead the service, even if there will only be a few family members present. A rabbi can conduct the service, lead the prayers, and generally handle all the arrangements.
Many families choose to have a small reception, luncheon, or dinner after the unveiling. As with a reception after a funeral or memorial service , getting people together for a meal after an unveiling can offer people a chance to connect and remember the person who died. A post-unveiling meal or reception can take place at a family home, a restaurant, or another location.