Not sure I understand. If you define your table headings using Word's table
properties feature, you shouldn't have a problem.

1. Select the row (or rows) at the top of your table that you want to appear
at the top of every continuation page.

2. Choose Table, Table Properties, click the Row tab, then check the option
for "Repeat as header row at the top of each page".

Now you can tab between table cells without fear of clobbering anything.
When you tab from the last cell in the table, Word will create another row
automatically.

If, on the other hand, you have a pre-defined table with places for user
input and other places where you have fixed "headings", then use Word's
Forms feature (look it up in help). A Form Field allows the user to enter
text, while protecting the boilerplate (headings, etc.) from being changed.
Just tell your users to press Enter within a Form Field when they need to
put in additional text. You could also define an Exit macro in a form field
to spontaneously create additional fields, but this is probably not
necessary.