VHS has a recognisable look because of how a home video recorder stored the picture. Each trait below is a consequence of the format, and each has its own control in the VHS tape section.
Soft detail: about 240 lines across the picture
A VHS recorder kept roughly 240 lines of horizontal detail per picture height, against well over a thousand in a modern 1080p file. Fine texture such as hair, foliage and text blurs sideways, while vertical detail is limited by the 480 or so visible lines of the TV picture. Softness filters the brightness along each line and snaps the picture to 480 tape lines, then adds the faint bright halo that a recorder’s sharpening circuit left beside edges.
Colour bleed: colour recorded at a fraction of the detail
VHS records colour separately from brightness, on a low-frequency carrier with only a few hundred kilohertz of bandwidth, roughly a sixth of what brightness gets. Colour therefore spreads well past the edges of objects and trails to the right of them, which is why a red jumper on tape seems to glow beyond its outline. Colour bleed blurs the colour signal far more than the brightness and smears it rightwards with an exponential tail, the same direction as a real recorder.
Head-switching noise and tracking
The tape is read by heads on a spinning drum, and the playback switches from one head to the other a few lines before the end of each field. On a CRT that ragged band was hidden by overscan; in a digital transfer it shows as a torn, noisy strip along the bottom of the frame. Head-switching noise recreates it. When the heads don’t follow the recorded tracks precisely, lines wobble sideways, a band of noise rolls through the picture and the frame occasionally drops a line; Tracking does all three, more of each as you raise it.
Scanlines, noise, dropouts and creases
Scanlines darkens every other tape line and nudges odd and even lines apart, like the two fields of an interlaced picture. Tape noise adds the horizontally stretched grain and blotchy colour noise of a weak signal. Dropouts are short white streaks where the magnetic coating was damaged or dusty, and Tape crease sends a band of distortion through the frame every few seconds, as a crinkled stretch of tape passes the heads.
The 4:3 frame
Almost everything recorded on VHS was 4:3. 4:3 frame keeps the centre of your picture and puts black bars at the sides of a widescreen clip (or above and below a tall phone video). The file keeps its original shape, so it still fits the platform you post to; the effect, the noise and the date stamp all sit inside the 4:3 picture.