Ms 365 online archiving

Question

Hi

Archiving emails older that 3 years on Ms 365 admin center

I wish to setup on line archiving of emails older than 3 years and my problems are:

1.i cant see the options to choose archiving messages older than 3 years,
2.if i create a new retention policy to archive messages older than default 2 years and enable that policy and archiving in user mailbox features,archiving does not happen.

please assist and guide me on how to implement online archiving in 365 admin center with outlook 2019 as client app?

Regards

support@zimsugar.co.zw