No iDevice can use an external mouse or trackpad device.
iOS has zero support for native mice/trackpad.ball support.
There is no pointing cursor to move on screen.
Your finger is the “mouse” OR you can use third party commonplace, cheap capacitive stylii or more expensive battery powered, so-called “active”, fine point capacitive still OR even more expensive Bluetooth stylii that utilise both pen pressure sensitivity and hand/palm rejection, that act as a mouse.
Some third party Bluetooth hardware AND iOS software keyboards have navigation arrows that can be used in place of a mouse/trackpad.
Some third party software keyboards have support for navigation arrows.
That stated you can move around the text "I" beam insertion point cursor by bringing up the iPad's virtual, software keyboard, do a two finger single tap to turn the entire keyboard area gray colored and into a gigantic trackpad area where you can easily control the position of the text insertion point "I" beam cursor.
You can highlight text and lines/body of text by doing a two finger double tap on the iOS software keyboard.
Then, do a single two finger tap on the keyboard area to fine tune the text selection.
That is as close to a mouse or regular trackpad that iOS is, currently, going to get.
Good Luck!
