Fiance Visa application queries

Hi,

My fiancee is going to applying from the USA for a visa to come to the UK for us to get married and live here. I have come across a few things I don't seem to be able to get any answers to so I was wondering if anyone on here may have the answers I am looking for.

Firstly, once she gets the passport with her fiancee visa, how long does she have to enter the UK? Is it anytime within the 6 months or is it 30 days from it being issued?

She is coming here to visit in September. Should we wait until after she has been to apply and book the biometrics date? This would still give us plenty time to receive the visa as our wedding is not until March 2020.

Thanks in advance for any help with this. Happy to provide any extra information.

Firstly, once she gets the passport with her fiancee visa, how long does she have to enter the UK? Is it anytime within the 6 months or is it 30 days from it being issued?

She will get a visa valid for 6 months and must enter the UK within that validity AND marry within that validity after the appropriate notice procedure has been done once in the UK.

She is coming here to visit in September. Should we wait until after she has been to apply and book the biometrics date? This would still give us plenty time to receive the visa as our wedding is not until March 2020.

She should apply for the Fiance visa after her visit not before.