A single line text field accepts a single line of text for each cell. You can put any text value you want into each cell.

The single line text field is best for short, unique pieces of text, such as the names of your friends, the names of your cats, or the names of your friends' cats. If you notice that you're repeating the same text values frequently in a column, you may want to consider using a single select, multiple select, or linked record field.