Choose a cell first or a digit first
In cell-first mode, tap a square and then enter its candidates. In digit-first mode, choose a number and tap each square where you want to add it.
You can switch modes in Preferences. The setting is saved in your browser.
Edit several cells at once
Turn on Multi, select several cells, and tap a number once. Sudoku Pilot adds or removes that candidate in every selected cell.
Undo reverses the whole edit if you selected the wrong group.
Fill all legal candidates in one tap
Fill all notes calculates the legal candidates for every empty cell. It is useful before looking for pairs, fish, or wings.
Auto-remove notes is a separate setting. When it is on, placing a digit removes that candidate from cells in the same row, column, and box.