Can I upgrade a Vostro 5630 with a 2 TB SSD later after buying?

Yes, you may. My understanding is that you won't invalidate your warranty simply by opening your case. However:

• your warranty won't cover anything that you install;
• if you need warranty repairs, Dell might request that you reinstall the original components;
• any damage you cause while inside your laptop is on you, the warranty won't cover it.

Whenever touching components or working inside a computer, wear a grounded wrist strap, also called anti-static wrist strap, ESD wrist strap, or ground bracelet. It's a cheap and sensible precaution. Rest the laptop on an anti-static mat or at least a reasonable alternative such as corrugated cardboard. (Repeatedly touching a metal case part is not sufficient mitigation with modern components.)

Yes, you can.

@filbert​ 

Hi, thanks for the answer.

One more query - does the Vostro 5630 have an additional SSD slot? I wanted to put in another SSD later.