Final answer:
To keep long text visible in a single cell, turn on text wrapping to ensure it remains visible by expanding the cell vertically.
Step-by-step explanation:
If you need to type in some text that is longer than the cell and you want to ensure it all remains visible on the screen, you should turn on text wrapping. This feature wraps the text within the cell, expanding the cell vertically to accommodate the entire text while keeping it within the cell's borders. This is different from text clipping, which hides overflow text, or spreading the text across other cells, which can disrupt the data structure. Auto-fill is not related as it has to do with filling cells with repeating or sequential data.