Does Angular Material have built in autosizing for textareas?

The answer is simple: it should be matTextareaAutosize, not just matAutosize: https://github.com/angular/material2/blob/master/src/material-examples/input-autosize-textarea/input-autosize-textarea-example.html

Caution! Apparently, this will be removed in version 7 and is currently deprecated https://material.angular.io/components/input/api#MatTextareaAutosize

PS: See also comment from @Simon_Weaver regarding the deprecation

For my work apply this to textarea:

Angular 7

<textarea cdkTextareaAutosize #autosize="cdkTextareaAutosize"cdkAutosizeMinRows="1" cdkAutosizeMaxRows="5"> </textarea>

Verify the scroll, in case of not showing verify the CSS property 'overflow: auto'