We always need specific details.
Like in your case we need to know
1. How do you want the vba script activated ?
2. What column will this value be entered into?
3. What value will this be?
For example you need to say something like this:
When I enter "Alpha" into any cell in column A I want that row hidden
Or when I click on a button hide all rows with Alpha in Column A
And how do you plan to unhide the row?