Tablet that keeps putting letters/words into my typing when I don'the want them (this is an example) [View all]

I do not know anything about tech and only recently got a tablet. I discovered DU and finally got enough confidence to reply recently. I don'the have knowledge of computer vocabulary and can't even cut and paste. I am leaving this un-edited to show you what my Samsung tablet does to my writing without any proofreading. Why does it assume certain letters/words? How can I stop this? I am not an idiot and was a teacher who knows grammar, etc. yet if I don'the triple check my writing I send stuff that is ridiculous. What do I do to stop this frustrating system?
Thank you.