Squid is an Android app that allows users to take handwritten notes on their devices using an active pen, passive stylus, or finger. The app also allows users to markup PDFs, import images, draw shapes, and add typed text to their notes. Users can quickly select, copy/paste, and move content between pages and notes, and organize their notes within notebooks. Squid also allows users to turn their device into a virtual whiteboard or give presentations by wirelessly casting to a TV/projector. Notes can be exported as PDFs or images and shared with others or stored in the cloud.

Squid is vector-based, which means that notes remain beautiful at any zoom level and on any device. The app includes a stroke eraser tool that allows users to erase entire letters and words quickly, and a true eraser tool that allows users to erase just parts of words. The selection tool allows users to change the color and thickness of their handwriting and resize a drawing without any loss in quality. Squid is designed to be both powerful and simple to use, allowing users to take notes quickly and efficiently.

Squid Premium is a paid version of the app that includes additional features such as premium backgrounds, the ability to import PDFs and mark them up like any other note, and additional tools such as a highlighter, true eraser, shapes, and text. Squid Premium also includes backup/restore and bulk export notes as PDFs to cloud storage providers Dropbox and Box. G Suite for Education customers can purchase Squid Premium in bulk using the Squid EDU Bulk License app.

Overall, Squid is a versatile note-taking app that allows users to take notes naturally on their Android devices using a variety of tools. The app is designed to be both powerful and simple to use, and includes features such as the ability to markup PDFs, organize notes within notebooks, and export notes as PDFs or images. Squid Premium includes additional features such as premium backgrounds, the ability to import PDFs, and additional tools such as a highlighter and true eraser.