Open a presentation, then do one of the following:
In a text box: Click the text box. If the text box already contains text, click once to select the object, then click again in the text where you want to place the insertion point.
In a shape: Double-click the shape. If the shape contains text, a word is selected; click again where you want to place the insertion point.
In a table cell: Click the cell to select it, then click where you want to place the insertion point.
In a title or caption: Click the title or caption to select the field, then click again to place the insertion point.
After you place the insertion point, you can use the arrow keys to move it.
Note: You can’t place an insertion point in placeholder text. When you click placeholder text, the entire block of text is selected. The insertion point appears only after you start typing.
Go to the Keynote app Copy and paste text in Keynote on Mac