can word convert number like if write 123 and it convert into one hundred twenty three

It depends on what you want to do, exactly. In the simplest case, you could use an ASK field to get input from the user and then display the number by inserting a REF field, to which you add the \* CardText formatting switch.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

IMHO a FILLIN field would be far simpler:
{FILLIN "Amount?" \d 0 \* Cardtext}
where the field braces (ie '{}') are created by Ctrl-F9 and you use F9 to get the prompt to input/update.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]