Can't keep the footer at the bottom

I customized the theme of the (invoice, quote, delivery note …) but when we print it directly from (Print) button in the system the footer aligned to “Body”, but when we created as PDF of email it shows perfectly at the end of the page

In one case, Manager relies on its new internal PDF generator. In the other, you are relying on the printer driver. So you may need two different versions of your custom theme, depending on how you will print and/or view and/or email.