According toThe Sun, the naturalization process takes five years.
After five years, Markle would be allowed to apply for citizenship.
The Home Office is able to make allowances for people remaining out of the country under special circumstances.

Michael Marziano, a senior immigration lawyer, elaborated on the requirements to become a British citizen through marriage.
“They must intend to continue to live together permanently in the UK.
It must be consistent with their continued intention to live in the UK permanently.”
