Although touchscreen mobile phones are widely used for recording informal text notes (e.g., grocery lists, reminders and directions), the lack of efficient mechanisms for combining informal graphical content with text is a persistent challenge. In the first part of the thesis, we present InkAnchor, a digital ink editor that allows users to easily create ink-based notes by finger sketching on a mobile phone touchscreen. InkAnchor incorporates flexible anchoring, focus-plus-context input, content chunking, and lightweight editing mechanisms to support the capture of informal notes and annotations. We describe the design and evaluation of InkAnchor through a series of user studies, which revealed that the integrated support enabled by InkAnchor is a significant improvement over current mobile note taking applications on a range of mobile note-taking tasks. The thesis also introduces FingerTip, a shift-targeting solution to facilitate detailed drawings. Occlusion caused by users' finger on the screen and users' uncertainty of the pixel they interact with are resolved in FingerTip via shifting the actual point where inking occurs beyond the end of the user's finger. However, despite a positive first impression on the part of prospective end users, fingertip turned out only passable on the drawing experience for non-text content. Combining the results of InkAnchor and FigerTip, this thesis does demonstrate that a significant subset of mobile note taking tasks can be supported using focus+context input, and that tuning for hand drawn text input has significant value in the mobile smartphone note taking and sketch input domain.