how can i use a - voltage on input to make high on output
By wiring up your input and output correctly, if necessary with additional components, and writing a small program.
Did that help you? If not, you should take some time to read about the basics of the Arduino in the tutorial section, try them out on your hardware and understand them. If after this you still have questions, please take the time to explain with a little more details what you're trying to do, what kind of voltages you're dealing with, what you already tried, what worked and what didn't. Then you'll get answers that will help you.
Vague one-line questions will get you similar results and only waste everyone's time.