A worksheet is a grid of cells, each named by its column letter and row number: B3 is column B, row 3. Click a cell and type to fill it; Enter confirms and moves down, Tab confirms and moves right, Esc cancels.
What you type decides what Excel stores:
- Numbers sit on the right of the cell and can be added up. Typing
$1,250 or 15% stores the number (1250, 0.15) and formats it for you.
- Text sits on the left. A number that sits on the left was stored as text, often after a paste from another system, and SUM skips it.
- Dates like
3/16/2026 are stored as numbers too (days since 1900), so you can add days to them.
Typing into a cell replaces what was there. To change part of it instead, press F2 (Mac: Ctrl+U) or double-click the cell.