You can access and pay for Drawboard PDF PRO by selecting any of the PRO features then following the prompts.
(There is also a three day trial available)
These features include:
- Document Builder
- Measurement Tools
- Protractor with Ruler (example shown below)
- Grid and Line templates and overlays
Tap on any of these and then you will find a prompt that looks like the following:
From here you can select your 30 day, 90 day or 365 day option, then tap on 'Buy now' to complete your purchase.