```python
import pandas as pd
df = pd.DataFrame({'Name': ['John', 'Mary', 'Peter'], 'Age': [20, 25, 30]})
Save the DataFrame to a CSV file
df.to_csv('data.csv', index=False)
```
This will create a CSV file named "data.csv" in the current working directory and save the DataFrame to it, excluding the index.
Similarly, you can use `to_excel` to save the DataFrame to an Excel file, `to_json` to save it to a JSON file, and so on.