Whether and whither are easily confused words.
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’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Whether (pronounced “weh-thuhrr”) is a conjunction. It is used for comparisons between two options. For example, at breakfast, I don’t know whether I want a muffin or bagel.
Whither (pronounced “wih-thurr”) is a verb. It’s another way of saying “where?” “For what purpose?”
The following story uses both words correctly:
Whitt was overthinking what his major should be in college. He didn’t know whether to pursue law, medicine, computer science, or engineering. Whither was his destiny? Which would fulfill his highest purpose?
As he gazed at the ceiling, his older brother Waylon passed his door. He leaned in. “What’s shaking, man?”
“I don’t know what my major should be: law, medicine, computer science, or engineering.”
“I’d go engineering or computer science, man. Invent stuff. Bring things that didn’t exist into being. Solving people’s dramas and maladies is too frustrating; then they sue you for trying.”
Waylon often got more credit for his humor than for intelligence. He had a way of simplifying decisions that had too many factors. Computer science it would be!