Pipedrive automatically syncs your phone and computer.
However, if you create something on your mobile device, or on your computer, and it doesn't appear on the other device, you can manually sync by dragging your finger down the screen on any view. If successful, a spinning circle will appear briefly at the top, then providing both your mobile and computer are online, both will be in sync.
Alternatively, you can also trigger the full data sync on the 'More' menu and tapping 'Synchronize Data'. You can find the 'More' view on the app's main menu.