Peek, peak and pique are three words that sound the same but have completely different meanings. The three words are homophones. If you accidentally use the wrong word on social media you can almost guarantee the grammar police will come after you.
Peak has several meanings. It is the highest point on a mountain. It can also mean high point as in peak sales or the peak of your career. To remember the correct spelling, Merriam-Webster suggests remembering that the "A" in peak is the most mountain-like letter in the alphabet.
Peek means to take a quick look at something. For example, "She peeked over the fence to see what was going on in her neighbor's yard." The spelling of peek might come to you if you can visualize seeing a word from your childhood, such as peekaboo. You could also think of it being a perfect masculine rhyme with the word seek.
Pique means to arouse one's curiosity. For example, "Opening the box of yarn piqued the cat's interest."
The word combination sneak peek tends to trip people up because the "ea" in sneak makes them want to use it incorrectly in peek. A lot of people type it incorrectly as "sneak peak" on Twitter. There was an a Twitter account, @StealhMountain, that would notify users if they misspelled "sneak peek." Many Twitter users do not realize they are making the typo.
Here's a helpful video with Dr. Clare Lynch explaining the meanings of the three words.