can I add an iPhone without a data plan, just a phone line

Ok, figured I’d have to ask T-Mobile. So it’s for an elder person who has the latest flip phone but it’s too hard to see and doesn’t save voicemail. Literally all they need is a phone, be able to save contacts and have voicemail. Will never use any part of the rest of the phone (which is a shame) but is happy to pay for the better phone. Thanks