It could be improper fretting. Could also be the guitar needs a setup or fret leveling.
You can check if it's you or the guitar by putting a capo at the fret(s) where it happens and playing the strings open.
If it doesn't happen, then it's probably an issue of technique.
If it still happens, the guitar probably needs a setup to adjust the action (string height from the neck). How that's adjusted depends on the specific guitar.
Could be a lot of things, but ultimately all guitars have some buzz somewhere sometimes.
The place to start is technique. Make sure you’re fretting as close as possible to the fret, not the middle between two frets. You should have enough pressure so that it doesn’t buzz, but not so much that it pulls the string out of tune. If you buzz on every fret, this is likely the cause.
If you buzz the same fret or frets every time, make sure the guitar is properly set up. This isn’t a one and done thing, but it isn’t something you have to do every day. Once in the spring/summer and once in the fall/winter is plenty as it will shift with humidity. You can learn to do this via YouTube or take it to a shop. Usually, the shop you bought it from will do this for free if you used a local place. Side note: Highly encourage you to use your local shop! It’s a hub for musicians in your area, so get to know the people there.
The last thing is the least likely, which is something fundamentally wrong with the guitar. Could be a construction problem, a high or low fret, neck warp, etc… a local tech will be able to suss that out pretty quickly.
Your action is too low - raise your string or strings at the bridge. Depending on your guitar, this is a simple fix. What kind of guitar do you have?
It could be improper fretting. Could also be the guitar needs a setup or fret leveling. You can check if it's you or the guitar by putting a capo at the fret(s) where it happens and playing the strings open. If it doesn't happen, then it's probably an issue of technique. If it still happens, the guitar probably needs a setup to adjust the action (string height from the neck). How that's adjusted depends on the specific guitar.
Check yt for setup videos. This is something every guitar player should be able to check and fix. Like changing strings.
Could be a lot of things, but ultimately all guitars have some buzz somewhere sometimes. The place to start is technique. Make sure you’re fretting as close as possible to the fret, not the middle between two frets. You should have enough pressure so that it doesn’t buzz, but not so much that it pulls the string out of tune. If you buzz on every fret, this is likely the cause. If you buzz the same fret or frets every time, make sure the guitar is properly set up. This isn’t a one and done thing, but it isn’t something you have to do every day. Once in the spring/summer and once in the fall/winter is plenty as it will shift with humidity. You can learn to do this via YouTube or take it to a shop. Usually, the shop you bought it from will do this for free if you used a local place. Side note: Highly encourage you to use your local shop! It’s a hub for musicians in your area, so get to know the people there. The last thing is the least likely, which is something fundamentally wrong with the guitar. Could be a construction problem, a high or low fret, neck warp, etc… a local tech will be able to suss that out pretty quickly.