Guys, how do i activate my pre-paid to be active for 1 year? thanks for helping

Thanks for your prompt reply and sorry for being vague.

I mean I am with digi post paid but i have another pre-paid number which i plan to give it to my father-in-law. He doesnt use the phone that much. So how do i activate the 365 days validity and how much minimum credit do i need to top up so that i can qualify for the 365 days validity?

Thanks for your help

Thank you very much.. sorry if this is a repeat question.