Hello missmvmaria,
In addition to the yellow tint/color showing for videos you record, are you noticing if the display of the iPhone is showing a yellow tint in all applications and functions? If so, it's possible that Night Shift may be enabled. This feature can be disabled in Settings > Display & Brightness > Night Shift. Also, if True Tone is enabled, tap the green toggle to disable that feature and test to see if the issue persists. You can also find these steps outlined in the following article, along with additional display settings.
Adjust the screen brightness and color on iPhone
If the issue continues after disabling those features and you're not seeing a yellow tint in other apps and functions, try recording a video in a different lighting environments to help rule out external factors. For example, if you're noticing this issue when recording videos indoors, try recording a video outside to see if the issue persists.
Let us know how that goes!