How should a text be placed in a fillable text field without losing its format and style?

When I copy a text from Microsoft Word into the fillable field, all the styles of that text are deleted, for example, the font size is lost, bold and italics are completely lost, ...  and a plain taxt remains in the field.

How should a text be placed in a fillable text field without losing its format and style?

Is it possible to create this feature with JavaScript?