Choose the plan in Create in on the New task tab, then use that one.
Pick people with + Assign on the New task tab, then use them.
The tag's text is set under Tag text.
Preview:
{department}
Variables work in Prefix, Text, Suffix and the template: any profile field, e.g. {jobTitle} or {extensionAttribute1}. The template also takes {prefix} {base} {suffix}.
{jobTitle}
{extensionAttribute1}
{prefix}
{base}
{suffix}
Sync Tasks on the ribbon always works, whatever is chosen here.
Settings shown in grey are set by your organization.