PDFs are really useful files, letting you view documents of all types, with text and images, on almost any devices. Workplaces use them a lot which means that your work phone can fill up with PDFs pretty fast.
To save space, Compress PDF allows you to make your PDF files smaller right there on the device, claiming back storage.
The compression happens on the app’s servers so it doesn’t even use your battery to power this process. This is a very fast app, but it looks quite basic and does mean you have to trust them with your files.