hope this helps :)

<FormControl fullWidth>
    <InputLabel shrink>Label</InputLabel>
    <Select label="Label" defaultValue={undefined} notched>
        <MenuItem value="1">One</MenuItem>
        <MenuItem value="2">Two</MenuItem>
    </Select>
</FormControl>

<TextField
    label="Label"
    slotProps={{
        inputLabel: {
        shrink: true,
        },
    }}
/>

https://stackblitz.com/edit/vitejs-vite-jsxsscjo?file=src%2FApp.tsx