Need and knead are easily confused words and homophones.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It suggests what word you may want to save time, but quite often, its suggestions couldn’t be more off base and produces humorous results.
Need is a verb. It means a requirement that must be fulfilled. For a human to survive, it needs food, air, water, and human contact.
Knead is a verb. It means to mould and pound dough to get the gluten evenly distributed and get bubbles out. Clay for pottery is also kneaded before it is shaped into a pot.
The following story uses both words correctly:
Nesiah kneaded dough and baked rolls every weeknight at the bakery. She worked hard at two jobs because she needed the money for college.