Transfer windows mobile to iPhone - help

A family member has been using a windows mobile (Lumira) and now got an iPhone.

I’ve managed to upload contacts into his outlook account and download them into the iPhone. I’m backing up photo by photo into OneDrive, luckily he hasn’t got too many.

But the whole process is a nightmare. And I can’t figure out how to move text messages (SMS) and I’m hoping that Whatsapp stuff moves across with a OneDrive backup.

Am I doing it all wrong? Is there an easier way? process? app?

(Yes I know, I should have advised to get an iPhone in the first place LOL).

Thanks @Wolfie

Whatsapp offers the option to back up to one drive. It’s good because it’s a local copy, but makes me nossos cause I’ ve never done it before

I should have known better that it’s never a good idea to give IT support to family members :rofl: :rofl: