MYOB Live Contacts has a Position Description but you can't import into this field.
I've got your screen-shot of "Fields required for Contacts" and there is no field for Position Description.
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Status added:
Open
Hi Huirae, thank you for your question. There is no way to do this currently so I've split it to a new Idea. The priority of these updates is based on community feedback so it would be great to see other users that would like to see this vote and comment to show their support.