How does saas product companies handle payments in case of large or medium sized clients. What if Employees are reluctant to pay using their personal cards? What if the company does not have a corporate credit card.
Depends. If the order is a few thousand dollars, you should have it setup to let them wire you the money or even checks (if the company is in the US).
Normally, for products up to $2K, companies take care of it with credit card. For higher products, you should encourage them to contact you. If you check a few SaaS companies, they have an enterprise plan with no details, encouraging you to contact them directly to find out more.