Setting Bin in Mail to regularly auto empty
How do I set up my Bin to automatically delete after a time period.
I have an iPad and iPhone but not a Mac.
I used to be able to set up my Mail bin to automatically delete old unwanted emails by opening Accounts, selecting a mail account. When opened there would be three buttons across the top and I could select one which would then enable me to set up the auto delete after ... time. Those buttons do not appear.
iPhone 11