Horizontal alignment (Long text field)

Hi, apologies in advance if i’m missing something very obvious here. I’m trying to create a shipping label, pulling the name from a single line text field, and below that the address from a long text field.

I want all the text to be aligned centre, however on the long text (address) the option is greyed out.

Vertical alignment is available, but that’s not what i’m after. Is it not possible to centre-align my text?