The best way to set up a Word document is to give each heading a style and name. So from the main heading down to sub-headings, they would be named
A Head
B Head
C Head
D Head
E Head

or something similar.

You can decide what style each heading has. So, for instance:
A Head = 30 pt. Times Bold Centered
B Head = 22 pt. Arial Bold Centered
C Head = 16 pt. Times Bold Left
D Head = 12 pt. Times Bold Italic Left
E Head = 10 pt. Arial Bold All Caps

(Just a quick example)

The point is that you select each heading and give it a style name.

When the typesetter/book designer imports the Word doc into InDesign or Quark, they will give all the headings different styles & fonts. But it will be easy for them to know what level of heading each one is b/c you’ve set up the style names.

So, it’s not important what particular font you use. What’s important is that you give each heading a style name. Without styles in the Word doc, the book designer might typeset the headings at the wrong level. They might confuse a Level C head with a Level D head in the manuscript if they are both in the default “Normal” style, even if they look different.

Using style sheets in Word will save you and the book designer lots of time, and it will ensure that your book is formatted correctly.