The difference is subtle for some and greater for others.
In the general sense, magic is what you see when David Copperfield makes an elephant disappear on TV, or it can also encompass one of the many street magic celebrities. Magic is theatrical, fun, and always a way to learn or figure out the illusion being performed. It is a profession that goes back to the early 19th century.
This is how Wikipedia describes the word magic and notes the first modern entertainer to be Houdini. “Magic, which encompasses the subgenres of illusion, stage magic, and close up magic, is a performing art in which audiences are entertained by tricks or illusions of seemingly impossible feats using natural means. It is distinguished from paranormal magic, which are effects claimed to be created through supernatural means. It is one of the oldest performing arts in the world. Modern entertainment magic, as pioneered by 19th-century magician Jean Eugène Robert-Houdin.”
Although, at times, the word magic and magick are used interchangeably, there are slight differences. From my research, the word Magick was made popular and fashionable by Ron Hubbard and Aleister Crowley starting in 1875 and quickly took on a following by Wiccans and other spiritual movements. Yet Magick goes back a lot more father in the past and well beyond Crowley's marketing and those that came after him.
The practice of Magick or Magic started well before Christianity and well before any organized religions. It was created when the people of this planet started to gaze upon the stars and developed systems around astrology, geometry, masonry, and other knowledge later used to build great cities, tell the future, and protect against things to come.
Magick is not good or bad. It is not positive or negative. It is what you make of it and what you manifest through it that gives it meaning. There is nothing evil about it. Nothing bad is waiting for you around the corner or hiding in the shadows. It is based on your “true will” placed into something for an outcome to occur.
You can easily equate Magick to both people of religious fate and those who follow no organized religion. As an example, putting an intention and your will into prayer for a good outcome to God, Jesus, or a Saint to some is considered Magick. It is the intention and the manifestation of something good to come to you through the guidance and religious power of God, saints, or others. Whereas miracles are generally not considered Magick because they are not from your will but the power of spiritual beings or guides, anything you create through your own focused intent could be considered Magick.
Like any religion or spiritual aspect in this world, some will dispute using the word magick and state everything theatrical and supernatural are defined as magic. Yet, you can always use the word magick to separate yourself from the obvious differences for those who want to get specific.
There is a lot more to this than just the general topics discussed above. For those that want to go deeper, check out this Author, Silver Ravenwolf. She writes some excellent stuff on the topic and blends a modern approach to her teachings and writings. These are a few good books to start with.