Applying for British Citizenship after surname change

I am British Citizen. My wife has been in this country since 1985, has Indefinite Leave to Remain, and has completed all the tests. She still has Indian passport. Now she wants to apply for British Citizenship.

In 2017, she changed her surname. At the time, she had valid Indian passport with expiry date of 2020. In 2022, she needed to travel to India in a hurry for a family emergency and needed to renew her passport. Renewal under new name was a lengthy process more geared to cater for someone living in India. So, the decision was made to renew her passport under old name.

What I want to know is:

1) What is the process for obtaining British Citizenship?
2) The passport being renewed under the old surname after change of surname; would this cause any issues?

Many thanks in advance

She needs to apply using form AN, read the guidance here https://www.gov.uk/government/publicati ... n-guidance
The name change can be explained in a cover letter - I expect she will need to get an Indian passport in her new name once the time comes to apply for her British passport, but it shouldn't cause an issue for citizenship.