Numbers are typically formatted as General or Numbers. But you might want Excel Online to treat certain types of numbers as text. For example, credit card numbers or zip codes that aren’t going to be used in calculations. To do that, you can apply the Text format. Here’s how:
Choose the cell or cell range that has the numbers you want to format.
Click Home > Number Format > Text.
Tip: If you don't see Text, scroll to the end of the list.
Note: Numbers formatted as text are left-aligned in cells.
Additional information about numbers formatted as text
To use decimal places for numbers stored as text, you can manually include the decimal points.
When you enter numbers that begins with a zero, Excel automatically removes the zero. For example, when you enter product codes like 0784367998, Excel changes it to 784367998. To prevent this, select the cell, cell range, or column and apply the Text format before entering or pasting the numbers.
You can also use the Text function to change a number to text.