For a better understanding of Box, see the example below

@Composable
fun BoxExample2() {
Box(
modifier = Modifier
.background(color = Color.LightGray)
.fillMaxSize()
) {
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.TopStart),
text = "TopStart"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.TopCenter),
text = "TopCenter"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.TopEnd),
text = "TopEnd"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.CenterStart),
text = "CenterStart"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.Center),
text = "Center"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.CenterEnd),
text = "CenterEnd"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.BottomStart),
text = "BottomStart"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.BottomCenter),
text = "BottomCenter"
)
Text(
style = MaterialTheme.typography.h6,
modifier = Modifier
.background(Color.Yellow)
.padding(10.dp)
.align(Alignment.BottomEnd),
text = "BottomEnd"
)
}
}