Once arrangements are under way, the couple plan to settle down with baby Archie in Canada, with Meghan expected to launch a new charitable foundation in the UK in spring.
Meghan and Harry pledged to "continue to uphold the values of Her Majesty".
Though Buckingham Palace did not comment on Harry and Meghan's security arrangements, they did say there "are well established independent processes to determine the need for publicly-funded security".
In a public statement addressing Megxit, the Queen said she was happy that they had found "a constructive and supportive way forward", stating that Prince Harry, Meghan and Archie "will always be much loved members of my family".
She announced she was "particularly proud of how Meghan has so quickly become one of the family".
"It is my whole family's hope that today's agreement allows them to start building a happy and peaceful new life," the Queen said.