How to print a text document to an unusual size paper.

I want to print a text document written on LibreOffice to a 4.5 x 6.6 in. paper. How can I do this?

First step:
You edit the page-style(s) you use and set your page size.

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Then you need to convince your printer it has this format, so you can print on this. (My current Epson always complain, if the setting are not identical.)
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Sometimes it is easier to export to pdf first, then print with Acrobat reader (for Windows).

This might (probably does) mean changing a setting on the the printer itself after you have loaded the 4.5" x 6.6" paper.

Anything more specific will likely require details, This is the guide - How to use the Ask site? - #3 by Hrbrgr