You can follow this tutorial.
I'll give the main steps here just in case but you'd better have a look at the link above:
Set a Different First Page
- Start with a blank Word document.
- Change the Margins (Page Layout tab, Page Setup group, Margins)
to what the second page and following pages should be.
- Choose Edit Header. (Insert tab, Header & Footer, Header, Edit
Header)
- In Header & Footer Tools, Design tab, Options, check Different
First Page.
Create the First Page Margins
You are not really setting margins, you’re manipulating other Word features to act like margins.
Top and Bottom Margins
- Go into the header or footer on the first page.
Change the top or bottom margins.
The quick way is to push your Enter key as many times as you need to
create the distance for the margin spacing – turn on the Ruler and
watch the left side ruler to get the distance close to what you want. Remember that by default the header or footer starts
one-half inch from the edge of the page, so if you need a 2 inch top
margin, the header will be 1.5 inches tall.
The more precise way would be to change the Paragraph Spacing (Home
tab, Paragraph group, Paragraph dialog box). Paragraph Spacing
appears measured in points, but you can type in 1″ or 1.5″ and Word
will convert it to points for you (36 points is one-half inch, 72
points is one inch, 144 points would be two inches). Set the After
spacing to whatever distance you need. To increase the bottom margin,
set the Before: paragraph spacing for the footer.
Left and Right Margins
If you need the left or right margins wider, insert a borderless, empty text box into the header of the first page. If you need both the left and right margins wider, you’ll add two text boxes, one for each side.
- In the header on the first page, in the Insert tab, Text group, Text
Box, Draw Text Box.
- Click and drag to draw the text box from the header all the way down
to the footer.
- Right-click on the text box, choose Format Text Box. In the Colors &
Lines tab, set the Line Color to none, to get rid of the border on
the text box.
- If you know you want the left margin to be two inches wide, go into
the Size tab and set the Text Box Width to two inches. Position the
text box at the very edge of the page and the text box will create
the look of a two inch left margin.
- In the Text Box Tools, Format tab, Arrange group, Text Wrapping, set
the wrapping to Square.
- If you need to change the right margin, could copy and paste the
text box you just created, and move it to the right side of the
page.
- Close out of the header or footer on the first page.
Regards,