Trending @Capgemini; If I do any course like Coursera, Udemy then that certification will be valid till my employment in Capgemini or for lifetime?

Udemy, coursera course certifications are worthless

Download the certificates, send to your personal mail. They're valid.

Besides, those certificates aren't really worth it. Udemy, Coursera etc. are just to upskill yourself. If you want to showcase on resume, go for a certification.