Word Work app lets you setup custom trace sheets for students to trace words. You can create a list of a few custom spelling words for a student to work on, or simply have them work on writing their own name.
You can choose a small, medium, or large size tracing font to allow for different skill levels. Tracing sheets can be oriented in portrait or landscape depending on your preference. You can save multiple trace sheets to flip between.
You can trace the words with your finger, or with a stylus. Once traced you can clear the page and trace it again, or switch to a different sheet.
TIP: When using a stylus, wear a thin glove on your writing hand. This prevents the iPad from sensing a "touch" if the student rests their hand on or brushes their hand against the iPad while writing.