The Ipad's screen size becomes too large and difficult to manage

Since the size of iPad's physical screen is fixed at the time of manufacture. I presume you are asking about something else.

Is the screen showing only part of what it should, but larger than it should, requiring a lot of scrolling to see the whole page?

Is this happening all the time, or only in certain apps of websites?

Might you have accidentally engaged one of the accommodations for the visually impaired?