You will find the option to 'Become PRO' in the Settings tab. Tap "Learn More" to open the screen shown below. It will show you the major PRO features (such as unlimited exchange account connections, portfolio analytics, real-time prices, the ability to sync 5 devices, monochrome mode, etc.) and the annual subscription fee in your local currency. You can learn more about what comes with PRO here.
You can also purchase a lifetime PRO subscription with a one-time payment. However, this option is only available via the desktop app. Download our desktop app and sync it to your mobile device first, and then purchase lifetime PRO on your desktop app. Note: Using the desktop app will be at your own risk as the desktop app is outdated and we no longer offer support on it. To get access to this, email us at firstname.lastname@example.org.
Thank you for considering PRO!