Q:

how to change width of  without affecting  width

I have here 2 photos. 1 is my HTML page and the other one is my print page.
My question is, how am I going to make my print page the same as my html page? As you can see, the print page is less wide than the HTML page. 
Also, I want to ask how am I going to make the width of <th> longer without affecting the width of <td>? Is that possible?
Sorry, I don't have that much knowledge in CSS.
Print Page

HTML Page

and here is my code: 
<table width="100%" border="1">
    <tr>
        <th align="left" width="20%">II. Documentation</th>
    </tr>
    <tr>
        <td align="center">Subject Routine</td>
        <td width="20%" align="center">Person-in-charge</td>
        <td width="15%" align="center">Complied</td>
        <td width="10%" align="center">Date</td>
        <td width="17%" align="center">Remarks</td>
        <td align="center">Signature</td>
    </tr>
    <tr>
        <td>1. Travel Documents</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>2. National License</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>3. NAC Certificates/MARINA COP</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>4. Medical</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>5. POEA / AMOSUP Contracts</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>6. Flag License</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>7. US Visa</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>8. Joining Port Visa</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>9. Other Certificate</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
</table>

A:

To get a nice print page width use media queries for example: 
@media print {  
    @page {  
      margin: 30mm;
      size:297mm 210mm;  
    }  
}

Or use diffent stylesheets with different widths in stead of the same 100%
<link href="style.css" rel="stylesheet" type="text/css" media="screen">
<link href="style_print.css" rel="stylesheet" type="text/css" media="print">

And in the style.css add:
    table {width:100%}
And in style_print.css add:
    table {width:297mm}
Play with the widths untill you are happy in both ;)
Here are some great posts on how to set up CSS for printing: 
https://www.smashingmagazine.com/2011/11/how-to-set-up-a-print-style-sheet/
https://www.smashingmagazine.com/2015/01/designing-for-print-with-css/
Just add colspan="6" to your th to set the correct width of your first cell.

<table width="100%" border="1">
    <tr>
        <th colspan="6" align="left" width="20%">II. Documentation</th>
    </tr>
    <tr>
        <td align="center">Subject Routine</td>
        <td width="20%" align="center">Person-in-charge</td>
        <td width="15%" align="center">Complied</td>
        <td width="10%" align="center">Date</td>
        <td width="17%" align="center">Remarks</td>
        <td align="center">Signature</td>
    </tr>
    <tr>
        <td>1. Travel Documents</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>2. National License</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>3. NAC Certificates/MARINA COP</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>4. Medical</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>5. POEA / AMOSUP Contracts</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>6. Flag License</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>7. US Visa</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>8. Joining Port Visa</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
    <tr>
        <td>9. Other Certificate</td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
</table>

