Here are the steps to save a webpage as a PDF:

1. Open the page you’d like to keep.
2. On the top left-hand corner, click File > Print.
3. Alternatively, press Ctrl + P (Windows) or Cmd + P (Mac).
4. Under the ‘Destination’ section, click Change... > Save as PDF.
5. Click the ‘Save’ button, pick the name and location for your PDF.

You can save a webpage as a PDF on any installed web browser such as Google Chrome, Microsoft Edge or Mozilla Firefox . If you're a Mac user, you can use the native Safari browser to save a webpage as a PDF.