we will be hosting a student portal shortly and we want to give our seniors email addresses, we already have their database of passowrds and usernames, how can we use that database to open accounts?

The answer is "Yes it is possible. You need to have a good understanding of how Cpanel works though"

I am not 100% sure what you are trying to achieve, please elaborate a little more.

I want to use a currrent database I have , of usernames and passwords, to create email account automatically,