Thousands of fans have flocked to Ms Presley’s childhood home in Graceland to pay tribute to the late singer-songwriter.
The mother-of-four, died of cardiac arrest aged 54 earlier this month.
Ms Presley’s body was on display to the public during the livestreamed memorial at family esate where she grew up with her father Elvis.
The service began with the singing of “Amazing Grace” by Jason Clark & The Tennessee Mass Choir.
In a message on the order of service, the Presley family had written: “We would like to express our heartfelt gratitude for the love, compassion and support you have shown our family during this difficult time.
“We will always be grateful.”
Ms Ferguson and Ms Presley became firm friends after meeting in the US in 2009 and the pair called each other “Sissy”.
Speaking during the celebration of Ms Presley’s life, Ms Ferguson said: “My late mother-in-law used to say that nothing can be said can begin to take away the anguish and the pain of these moments because grief is the price we pay for love and how right she was.”
Filmmaker Joel Weinshanker had said Lisa Marie Presley requested for her funeral to “not be sad” and that they will try to honour her wish in the coming proceedings.
This was followed by Pastor Dwayne Hunt delivering a prayer, saying: “While her light has gone out, she leaves this light to her children and her mother so that they can rise above the darkness of this grief.”
The mansion, which Lisa Marie Presley owned, has been turned into a museum and tourist attraction that hundreds of thousands of fans visit each year to celebrate the life and music of Elvis, who died in 1977.
The property in south Memphis was a place of sadness and somber memories on Sunday.
