You can add text directly to a table cell and change its appearance—including its font, color, size, and alignment.
If you want to add text outside of a table cell, you can add a text box to a sheet. A text box is an object that can be modified like most other objects; you can rotate it, change its border, fill it with a color, layer it, and more. The text inside the box can be formatted like any other type of text.
You can also add text in a shape.
Tap 
, tap 
, then tap Text. A text box is added to your sheet (you can change how it looks later).
Double-tap the placeholder text, then enter your own.
Drag the text box to where you want it on the sheet.
Resize the text box, if necessary, by selecting it and dragging any selection handle (the blue dots).
To delete a text box, tap it, then tap Delete.
To edit text, you must select it first. To edit within a word or paragraph, place the insertion point where you want to begin.
Select a word: Double-tap it (or tap the text, then tap Select).
Select a range of text: Double-tap a word, then move the selection handles to include the range of text you want to select.
Select text and its formatting marks: Double-tap a word, then move the selection handles beyond the current text.
The selection includes the entire paragraph and its formatting marks (invisibles). You can move the selection handles up or down to include or exclude paragraphs from the selection.
Select a paragraph: Triple-tap it.
Double-tap a shape or text box to select a word within it.
Touch and hold within a line of text until a magnifying glass appears.
Note: You can’t place the insertion point in placeholder text. When you tap placeholder text, the entire block of text is selected and is replaced when you begin typing.
Drag your finger over the text until the insertion point is where you want it, then lift your finger.
You can use gestures to move the insertion point to a particular point in text:
Left or right: Swipe left or right with one finger.
Beginning of the current word or the beginning of the previous word: Swipe left with two fingers.
End of the current word or the end of the next word: Swipe right with two fingers.
Beginning or end of the current line: Swipe left or right with three fingers.
To quickly reuse a selection of text, copy and paste it.
Select text, then tap Copy.
Place the insertion point in text, or select some text, then tap Paste.
You can copy just the style of selected text and apply that style to other text.
Select text, tap Style, then tap Copy Style.
You may need to tap 
to see Style.
Select other text to apply the style to, tap Style, then tap Paste Style.