What is the ruling on working for a software company that builds websites for American insurance companies, knowing that a part of these companies' work is life insurance?

There is no objection to working for a software company that creates websites for renewable content, as long as it is not related to unlawful (haram) material. However, it is not permissible to work with insurance companies to set up pages for them, because commercial insurance is based on forbidden uncertainty (gharar) and gambling. If one does work with them, the earnings are ill-gotten wealth (mal khabith) that must be disposed of by giving it to the poor and needy. It is permissible for a needy poor person to take from it an amount sufficient for their needs.