I'm using mui textfield per documentation here:

CodePudding user response：

The reason that there's no documentation on how to make a fatter "caret" is because this is not currently supported in browsers. You can change the caret color using CSS (eg. caret-color: red;), but if you want to mimic a console's "fat" caret, you may have to add your own element to the screen and then move it based on the input entered. Here is an old example of one way to do it and another which would also require your own JS implementation.

There is a proposed revision for caret-shape: block;, which appears to be what you're looking for, but that is not currently supported.