Is Zakat due on money borrowed to establish a contracting company after profits appear, and is Zakat on the capital or on the profits, and is it before or after settling the debt?

Religion does not prohibit Zakat. If you own the nisab (minimum amount subject to Zakat) and a hawl (lunar year) has passed on it, then Zakat becomes obligatory. Fixed assets owned by companies for acquisition and use, such as real estate and machinery, are not subject to Zakat. Rather, Zakat is due on liquid funds and trade goods. To pay Zakat on your share in a company, you enumerate the Zakat-eligible assets and calculate your percentage of them, then you pay 2.5% on that. Profits generated from trade are subject to Zakat along with the principal capital, and a new hawl is not required for them. As for wages, they are subject to Zakat after being received and a hawl has passed on them.