Add text in Keynote on iPhone
To add text to a slide, you can replace the placeholder text or add a text box or shape, then type text in them.
Replace placeholder text
Double tap placeholder text, then type your own.
If the theme has placeholder text that you want to remove, tap the text once to select its text box, then tap Delete.
Add a text box
Text boxes are objects that can be modified like most other objects. You can rotate the text box, change its border, fill it with a colour, layer it with other objects and more. To learn more about customising a text box, see Intro to images, graphs and other objects in Keynote on iPhone.
Tap
in the toolbar, tap 
, then tap Text in the Basic category.A text box is added to your slide (you can change how the text looks later).
Drag the text box to where you want it.
If you can’t move the box, tap outside the box to deselect the text, then tap the text once to select the text box.
Double tap the placeholder text, then enter your own.
To resize the text box, drag the selection handle on the left or right side of the box.
To delete a text box, select it, then tap Delete.
Add text inside a shape
Double tap the shape to make the insertion point appear, then type your text.
If there’s too much text to display in the shape, a clipping indicator
appears. To resize the shape, tap it, then drag any selection handle until all the text is showing.
You can change the look of text inside the shape just like any other text on your slide.
To add a caption or label to an object, see Add a caption or title to objects in Keynote on iPhone.