1. You need to show the purpose of visiting the USA is linked to business purpose only.
2. You must ensure that your stay in the USA will be for a specific time period.
3. You need to show proof of funds to cover expenses in the United States.
4. You must provide evidence of compelling social and economic ties abroad.
5. You must provide proof of having a residence outside the US as well as other binding ties which will ensure your return to home at the end of the visit.

The above-mentioned requirements of B-1 visa are also applicable for applying visa to the USA from London.

For more details visit website - https://immigrationlawyerfl.com/business-working-visas/