It really depend on the camera type you use and you have that kind of filming need .
As a Youtuber,Blogger,or professional filmmaker,if you are just a learner then DSLR video camera has a bult-in microphone.but for the professional user you must need a external microphone.you must understand an excellent video always with perfect audio quality.to save your time and money.take careful to choose your ecternal microphone.
Cause on the marketing there are a lot of choice for external microphones for your video camera.
Like Fuji XH1 is a good choice for manual focus .
Fuji XT3 is for autofocus is a large priority
Lensgo dm1 is dslr lavalier microphone with 6 meter cable
lensgo dmm1 dmm2 is dslr shotgun microphone for 3 or 5 meters shooting distance.
lensgo dm200 dm300 dm30 is broadcast dslr microphone
lensgo 318c 308c 328c 338c 348c is wireless dslr microphone
Good lucy for you.
Video Camera suggestion is as following:
Canon 750D / T6i it is a great, cheap piece of equipment and has a mic input.
Canon 750D-its less pricey than the 80d but has adequate feeatures for good photography.
Or you cann just start from mirrorless camera from Panasonic and Olympus.