The question for today is whether your partner can work in the US with a K-1 visa. The answer is that it's going to be really hard. Let me tell you how this process works.
A difficult position
When a person receives a K-1 visa in their passport, they are able to enter the United States. The only document they have at the time of entry is just the K-1 visa. They won't have a social security card and they won't have any other proof of employment authorization. Most companies are not going to want to employ that person.
What I recommend in that situation is that once the K-1 visa holder arrives in the US, they need to get married very quickly. Then, they should turn around and file their green card application.
When you file a green card application, called I485, you are also able to request a temporary work card, an employment authorization document. The work card has a little notation on the form that asks if you would like the social security administration to give you a social security number.
The client should select yes, they want the social security number, and yes, they want the work card while they are waiting for the green card to be adjudicated. And that is a good strategy to get your K-1 visa holder working in the US as soon as possible. Contact me with any questions.