optical defects + PHP Output

Hi,

im using your plugin.
Basically, I am thrilled with the settings options and find the plugin good. Unfortunately, however, there are some things that do not work well for me. Below I would like to explain these.

1.) When I edit a mail, in my case the “order confirmation” and then send it as a test mail, I have the problem that the mail looks strange on different clients. In Outlook the mail is a disaster. The colors do not match at all, the arrangement is definitely not as I have configured it and buttons look completely different! What am I doing wrong here?

2.) Is it possible to include PHP?
I am using the Iconic Delivery Slots plugin and would like to arrange the delivery date and timeslot in a different position.
Here is the link to Iconic’s instructions:
https://iconicwp.com/docs/woocommerce-delivery-slots/get-the-delivery-date-and-time-for-an-order/
Here is the answer from support:
If you want to insert or display the delivery dates in different areas, you can easily do that using a PHP code.

Regards,
Dominic